Track develop branch

[nilp0inter]

To improve our response time whenever new versions of AutoFirma are available. We'll actively track upstream develop branches in our own develop branch, periodically building AutoFirma to find potential problems and address them.

• Create a new develop branch
• Create a new GitHub Workflow that updates the flake (to point to the HEAD of upstream), disables the cache and tries to build AutoFirma.
• Another GitHub Workflow should periodically check that the maven-dependency-hash values of the different projects are not changing, and PR accordingly.