Update rdkafka requirement from 0.28 to 0.29

[dependabot]

Updates the requirements on rdkafka to permit the latest version.

Changelog

Sourced from rdkafka's changelog.

0.29.0 (2022-10-29)

• Breaking change. Pass through errors from librdkafka in BaseProducer::flush, StreamProducer::flush, and FutureProducer::flush.

  Thanks, [@​cjubb39].

• Breaking change. Only provide NaiveRuntime if the naive-runtime feature is enabled. This elides a dependency on futures-executor when the naive-runtime feature is disabled.

• Breaking change. Remove the deprecated StreamConsumer::start method. Use the more clearly named StreamConsumer::stream method instead.

• Breaking change. Rework the Headers trait to distinguish between headers with null values and headers with empty values. The Headers::get and Headers::get_as methods now return a Header struct with the following definition:

  pub struct Header<'a, V> {
      pub key: &'a str,
      pub value: Option<V>,
  }

  Previously, these methods operated in terms of key–value pair (&str, &[u8]).

  These methods now panic if presented with an out-of-bounds index. This simplifies their usage in the common case where the index is known to be valid. Use the new Headers::try_get and Headers::try_get_as methods if you need the old behavior of returning None if the index is invalid.

• Rename the OwnedHeader::add method to OwnedHeader::insert, for parity with the equivalent method for the map types in std::collection and to avoid confusion with the add method of the std::ops::Add trait. The method now takes the Header type mentioned above as an argument, rather than the key and value as separate arguments.

• Add the Headers::iter method to iterate over all message headers in order.

• Add the PartitionQueue::set_nonempty_callback method to register a callback for a specific partition queue that will run when that queue becomes nonempty. This is a more flexible replacement for the ConsumerContext::message_queue_nonempty_callback method that was removed in the last release.

• In BaseConsumer::rebalance_protocol and StreamConsumer::rebalance_protocol, handle null return values from the underlying librdkakfa API (#417). This avoids an occasional segfault in the rebalance callback.

... (truncated)

Commits

• 65520c8 rdkafka: release v0.29.0
• 9dc0294 rdkafka-sys: prepare changelog for release
• 6fb6d4f Merge pull request #457 from fede1024/oauth-callback
• 20cb2b4 Merge pull request #486 from gyfis/g/librdkafka-1.9.0
• f5b8bd7 rdkafka: add note about recv's cancellation safety
• f2ce9cc Merge pull request #470 from aarashy/aarash/improve-commit-offset-documentation
• a1ddbbe Improve documentation for Commit Offset semantics
• 2e4a373 Rework OAuth callback to avoid memory unsafety and follow conventions
• 86c8470 rdkafka-sys: upgrade librdkafka to v1.9.2
• 5f9cb6f rdkafka-sys: make CARGO_MAKEFLAGS optional
• Additional commits viewable in compare view

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