add deploy and asset update actions

[jeffpaul]

Description of the Change

This PR adds the WP.org deploy and readme/asset update actions to ensure we can automate future releases to the dotorg repo. Note that we'll still need to add the Sophi.io SVN_USERNAME and SVN_PASSWORD secrets to this repo once that WordPress.org account is created.

Alternate Designs

none really, but I suppose we could manually deploy to SVN but why?

Benefits

Speeds up releases to WP.org.

Possible Drawbacks

none identified

Verification Process

none, our next release will validate this deploy works

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Applicable Issues

n/a

Changelog Entry

### Added
- GitHub Actions to deploy releases and update readme/asset changes for WordPress.org

[jeffpaul]

@dinhtungdu will want to review each of these closely, especially the deploy action, to ensure we'd be pushing a correctly built plugin to dotorg.

[dinhtungdu]

We need a .distignore file to exclude the development files from the release