Use conventional tagging for GitHub actions

I noticed you're doing v1.0 and v1.1 tags for releases. This is nice, but it means that people have to manually update their action references every time there's a release: uses: szenius/set-timezone@v1.0 -> uses: szenius/set-timezone@v1.1.

This can be easily solved by pushing a v1 tag to your Git repo (no release required) and force pushing that v1 tag every time there's a v1.x release.