release: Release cloud_events 0.5.1

[github-actions[bot]]

This pull request prepares new gem releases for the following gems:

• cloud_events 0.5.1 (was 0.5.0)

For each gem, this pull request modifies the gem version and provides an initial changelog entry based on conventional commit messages. You can edit these changes before merging, to release a different version or to alter the changelog text.

• To confirm this release, merge this pull request, ensuring the "release: pending" label is set. The release script will trigger automatically on merge.
• To abort this release, close this pull request without merging.

The generated changelog entries have been copied below:

---

cloud_events

v0.5.1 / 2021-06-28

• ADDED: Add HttpBinding#probable_event?
• FIXED: Fixed a NoMethodError when a format declined to decode an http request

[github-actions[bot]]

All releases completed successfully.

Successfully released cloud_events 0.5.1