chore(main): release 1.28.0

[release-please[bot]]

:robot: I have created a release beep boop

1.28.0 (2024-02-15)

Features

• Allow setting of universe domain in environment variable (#520) (6e6603b)

---

This PR was generated with Release Please. See documentation.

[release-please[bot]]

:robot: Release is at https://github.com/googleapis/gax-php/releases/tag/v1.28.0 :sunflower:

[release-trigger[bot]]

Triggered job: cloud-devrel/client-libraries/php/googleapis/gax-php/release (2024-02-15T19:05:39.637Z)

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: