Pre release

[WoodenMaiden]

These changes allow to create gama-platform{-jdk}-unstable packages when the tag given is a pre-release tag.

If you trigger the action with the tag of a pre-release it will generate or update these packages, if it is a release it will remove them.

Links:

• the repo URL: pre-release-tests.gama-ppa-test.pages.dev
• the demo branch: https://github.com/WoodenMaiden/gama.ppa/tree/pre-release-tests

[RoiArthurB]

@WoodenMaiden Can you rename the package from gama-platform{-jdk}-unstable to gama-platform{-jdk}-alpha to follow the same wording as on the release page please :)

[WoodenMaiden]

Done :)