chore(main): release 2.21.4

[release-please[bot]]

:robot: I have created a release beep boop

2.21.4 (2024-06-18)

Documentation

• samples: Add code sample for optimistic subscribe (#1182) (d8e8aa5)

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[release-please[bot]]

:robot: Created releases:

• v2.21.4 :sunflower:

[release-trigger[bot]]

Triggered job: cloud-devrel/client-libraries/python/googleapis/python-pubsub/release/release (2024-06-18T14:46:10.667Z)

To trigger again, remove the autorelease: triggered label (in a few minutes).

[release-tool-publish-reporter[bot]]

The release build has started, the log can be viewed here. :sunflower:

[release-tool-publish-reporter[bot]]

:egg: You hatched a release! The release build finished successfully! :purple_heart: