Add GitHub Action for publishing new releases

[pverscha]

This PR adds a new GitHub Action that automatically pushes a new version of this package on NPM, and that automatically creates a new release on GitHub (which we still need to manually annotate with release notes).

[bmesuere]

I'm not too fond of automatic publishing "on push". Since this isn't something that is done a lot, a manual trigger using workflow_dispatch might be an alternative.

When triggering manually, it is possible to enter a variable which could be used to pass along a version number. Instead of parsing the number from the file, the action could use the provided version number and save it in the necessary files in the repo (even committing the changed file(s)).

[pverscha]

I updated the action so that it can only be started from a workflow. The new version number will be asked upon invocation of the workflow dispatch and the package.json file will be updated (and committed) with the new changes in this action.

[bmesuere]

I seem to have forgotten to add my suggestion to github:
I think a lot of the regex stuff can be handled by npm version