Automate the Flathub deployments of new versions.

[ChristianFeldmann]

Is your feature request related to a problem? Please describe.
Currently, the deployment to flathub must be performed manually. That is not a good state to be in. I found a github action that may be able to perform this: https://github.com/flatpak/flatpak-github-actions

Describe the solution you'd like
With each release, the new version should be built and deployed to flathub automatically.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.