Add release workflow

[michelegera]

This PR adds a new workflow to delegate the package release to the CI.

The workflow can be dispatched only manually and will perform the following steps:

• Check out the code, including all history for all branches and tags.
• Verify that the workflow is triggered for the main branch, and abort if not.
• Set the Git user name and email to the person (or app) that initiated the workflow.
• Install dependencies.
• Trigger the release script.