This is a sample github action that creates an rmskin package and automatically uploads it to a github release. Simply create a tagged release and the github action will automatically create the rmskin and upload it the newly created release for you.
Caution: This script is NON-VALIDATING, meaning the folder structure is archived AS IS. Also, plugins are NOT checked for the correct bitness.
When a release is published, the github action will automatically start running. Using Powershell, the action will first archive the contents of the RMSKIN folder to a .zip file. Then the Rainmeter custom footer is written to the file. It then changes the extension of the .zip file to a .rmskin file. Then the .rmksin file is automatically uploaded to your previously created release as an asset.
This makes it really easy to make a few changes to your skin files, create a new release, and have the new .rmskin automatically created and uploaded for you.
With this script, the folder structure needs to be exactly the same as how the Rainmeter rmskin packager does it. The folder RMSKIN contains an unzipped rmskin file previously created with Rainmeter.