Bump WordPress "tested up to" version 6.3 on trunk

[jeffpaul]

Description of the Change

This PR merges the WP "tested up to" version bump from #125 into the trunk branch to hopefully trigger the Readme Updater action and update directly on WP.org without needing a minor plugin release here on GitHub.

Closes #124.

How to test the Change

Changelog Entry

n/a

Credits

Props @jeffpaul.

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[peterwilsoncc]

LGTM based on a code read through.

I'm presuming this means the plugin has been tested with 6.3 so haven't repeated the process.

[jeffpaul]

Looks like this one didn't make it across to DOTORG, possibly something during the build step? https://github.com/10up/Ad-Refresh-Control/actions/runs/6155017917/job/16722073689. I do wonder with this action why we're bothering with building since we should just be looking for changes to trunk that are ONLY to the readme or assets and then pushing those across to DOTORG (which again shouldn't require a build)?

[peterwilsoncc]

I do wonder with this action why we're bothering with building since we should just be looking for changes to trunk that are ONLY to the readme or assets and then pushing those across to DOTORG (which again shouldn't require a build)?

The action looks for changes to other files and presumes there have been other merges to trunk if they are altered.

I think failing to build would cause the action to fail due as it would appear files have been deleted. What I don't understand is why the built files are changing as the lock file should prevent that. The only thing I have been able to think of is that the node version may be different and resulting if different output.