Update spring-boot's version to 2.3.4.RELEASE

[chenrujun]

• Update spring-boot and spring-cloud's version to latest released version.
• Update external dependencies' version according to spring-boot-dependencies and spring-cloud-dependencies

[gapra-msft]

Storage changes look good to me

[kushagraThapar]

@chenrujun I investigated this issue today, and seems like Azure Cosmos SDK has an issue with netty library version 4.1.52.Final

This issue is easily reproducible with ChangeFeedProcessorTest on this PR.
These are the error logs I am seeing locally.

2020-09-29 17:36:58,661       [main] INFO  com.azure.cosmos.TestNGLogListener - beforeInvocation: TestSuiteBase#beforeSuite
2020-09-29 17:36:58,669       [TestNG-method=beforeSuite-1] INFO  TestSuiteBase - beforeSuite Started
2020-09-29 17:36:58,747       [TestNG-method=beforeSuite-1] INFO  com.azure.cosmos.implementation.RxDocumentClientImpl - Initializing DocumentClient with serviceEndpoint [https://paged-flux-test-account.documents.azure.com:443/], connectionPolicy [ConnectionPolicy{requestTimeout=PT5S, connectionMode=GATEWAY, maxConnectionPoolSize=1000, idleHttpConnectionTimeout=PT1M, idleTcpConnectionTimeout=null, userAgentSuffix='', throttlingRetryOptions=RetryOptions{maxRetryAttemptsOnThrottledRequests=9, maxRetryWaitTime=PT33H20M}, endpointDiscoveryEnabled=true, preferredRegions=null, multipleWriteRegionsEnabled=true, proxyType=null, inetSocketProxyAddress=null, readRequestsFallbackEnabled=true, connectTimeout=null, idleEndpointTimeout=null, maxConnectionsPerEndpoint=0, maxRequestsPerConnection=0}], consistencyLevel [Session], directModeProtocol [Tcp]
2020-09-29 17:36:58,959       [parallel-1] INFO  com.azure.cosmos.implementation.RxDocumentClientImpl - Getting database account endpoint from https://paged-flux-test-account.documents.azure.com:443/
2020-09-29 17:36:59,156       [reactor-http-nio-1] WARN  io.netty.channel.DefaultChannelPipeline - An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
io.netty.channel.ChannelPipelineException: reactor.netty.resources.PooledConnectionProvider$PooledConnectionAllocator$PooledConnectionInitializer.handlerAdded() has thrown an exception; removed.
	at io.netty.channel.DefaultChannelPipeline.callHandlerAdded0(DefaultChannelPipeline.java:624) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.DefaultChannelPipeline.access$100(DefaultChannelPipeline.java:46) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.DefaultChannelPipeline$PendingHandlerAddedTask.execute(DefaultChannelPipeline.java:1463) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.DefaultChannelPipeline.callHandlerAddedForAllHandlers(DefaultChannelPipeline.java:1115) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.DefaultChannelPipeline.invokeHandlerAddedIfNeeded(DefaultChannelPipeline.java:650) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:502) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:417) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:474) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) [netty-common-4.1.52.Final.jar:?]
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) [netty-common-4.1.52.Final.jar:?]
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) [netty-common-4.1.52.Final.jar:?]
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [netty-common-4.1.52.Final.jar:?]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [netty-common-4.1.52.Final.jar:?]
	at java.lang.Thread.run(Thread.java:834) [?:?]
Caused by: java.util.NoSuchElementException: reactor.netty.resources.PooledConnectionProvider$PooledConnectionAllocator$PooledConnectionInitializer
	at io.netty.channel.DefaultChannelPipeline.getContextOrDie(DefaultChannelPipeline.java:1082) ~[netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.DefaultChannelPipeline.remove(DefaultChannelPipeline.java:417) ~[netty-transport-4.1.52.Final.jar:?]
	at reactor.netty.resources.PooledConnectionProvider$PooledConnectionAllocator$PooledConnectionInitializer.handlerAdded(PooledConnectionProvider.java:284) ~[reactor-netty-0.9.12.RELEASE.jar:?]
	at io.netty.channel.AbstractChannelHandlerContext.callHandlerAdded(AbstractChannelHandlerContext.java:938) [netty-transport-4.1.52.Final.jar:?]
	at io.netty.channel.DefaultChannelPipeline.callHandlerAdded0(DefaultChannelPipeline.java:609) [netty-transport-4.1.52.Final.jar:?]
	... 14 more

@moderakh @FabianMeiswinkel - we will need to debug this issue as this will block us / everyone moving to the latest netty version.

We can let others move by updating external_dependencies.txt file and keeping netty dependency for cosmos on current versions, but it will be an issue for us soon once we want to upgrade.

[kushagraThapar]

Please do not merge this as it will break azure-cosmos SDK.

[moderakh]

this should not get merged till cosmos db issue on newer version of netty is fixed.
Please don't merge this.

[kushagraThapar]

@chenrujun - It was a netty dependency issue in azure-cosmos Java SDK. I have fixed it through this PR - #16602

Once my PR is merged, you can rebase on the latest master and re-run the cosmos CI to check everything looks good.

[kushagraThapar]

@chenrujun - We have solved this dependency conflict issue here - #16604
Please rebase your PR with master and run the tests again to verify if the issue is resolved now.

[chenrujun]

/azp run java - spring - tests

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[yiliuTo]

LGTM

[chenrujun]

/check-enforcer override

cosmos db issue on newer version of netty is fixed