Update Java-WebSockets to 1.5.1

[nikoTM]

Breaking changes:

• this.CONNECTING and this.isConnecting() removed, since they were removed in Java-WebSockets Breaking changes in 1.4 TooTallNate/Java-WebSocket#753

EDIT:

Updated jar taken from here Java-WebSocket-1.5.1-with-dependencies.jar

[nikoTM]

@NathanaelA

Since Java-WebSockets seems to be using SLF4J for logging, this build will log the following errors:

System.err: SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
System.err: SLF4J: Defaulting to no-operation (NOP) logger implementation
System.err: SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

Can be solved by adding a gradle dependency with

implementation group: 'org.slf4j', name: 'slf4j-simple', version: '1.7.25'

But I thought it should be left to the plugin user to decide wether or not they want that dependency.