Add change and release workflow for update automation

[phunkyfish]

DO NOT MERGE YET

This workflow should allow easier kodi PVR API updates being triggered by the gh command locally on a dev machine. The hope is to automate API updates across all of PVR add-ons to reduce the maintenance burden.

First step is to test if it works. Note: The commands below will create a full release automatically.

After merge this can be done by installing the gh command and then trying to run:

1. gh auto login (https via a web browser should be fine)
2. gh --repo palinek/pvr.sledovanitv.cz --ref Matrix workflow run changelog-and-release.yml -f version_type=micro -f update_news=true -f changelog_text="-\ Release bump\\\n-\ Automation testing"

The above command will update the micro version number and add the changelog text where appropriate. Then a release will be created using the same details

[phunkyfish]

This can be merged now.

FYI: currently the workflow can only be used by the repo owner/maintainers.

[phunkyfish]

Please merge prior to binary add-ons branch for Nexus which will happen soon.