upkeep/325: Add blueprint.json

[Sidsector9]

Description of the Change

Closes #325

Adds blueprint.json file.

Changelog Entry

Developer - Support for the WordPress.org plugin preview

Credits

Props @jeffpaul @Sidsector9

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.

[github-actions]

@Sidsector9 thanks for the PR! Could you please fill out the PR template with description, changelog, and credits information so that we can properly review and merge this?

[jeffpaul]

@Sidsector9 mind sharing a URL that uses this file via the branch to test in WP Playground to validate its working as expected?

[jeffpaul]

@Sidsector9 this still needs the repo badge as noted in the task list in #325, see https://github.com/10up/maps-block-apple/blob/develop/README.md for an example

[dkotter]

Thinking we should set this to latest so we're not having to constantly bump this version

[dkotter]

Tested using the following playground link: https://playground.wordpress.net/#{%22landingPage%22:%22/wp-admin/options-reading.php%22,%22preferredVersions%22:{%22php%22:%227.4%22,%22wp%22:%22latest%22},%22phpExtensionBundles%22:[%22kitchen-sink%22],%22steps%22:[{%22step%22:%22login%22,%22username%22:%22admin%22,%22password%22:%22password%22},{%22step%22:%22installPlugin%22,%22pluginZipFile%22:{%22resource%22:%22wordpress.org/plugins%22,%22slug%22:%22restricted-site-access%22},%22options%22:{%22activate%22:true}}]}

Loads correctly for me, installing the plugin and taking me to the Reading settings