feat(master): c/build.sh: Add master branch support for next release

[rzr]

I believe developing on master would improve the developer experience, and it can reduce propagation of changes on each release (CI etc?).

For smoother transition master is currently building 8.x branch, we might want to switch to unreleased 9.x soon.

At the moment master uses Dockerfile-8.x (not duplicated), same with repo file. Later we could introduce master repo baseurl, and use it in an unstable Dockerfile.

Side note, would it make sense to use master by default if no arg passed ? If yes, I will do it in later change since it touches the API

For the record this change was tested using the following commands:

cd ~/mnt/xcp-ng-build-env # https://github.com/xcp-ng/xcp-ng-build-env
./container/build.sh master
cd ~/mnt/xcp-ng-release # https://github.com/xcp-ng-rpms/xcp-ng-release
~/mnt/xcp-ng-build-env/src/xcp_ng_dev/cli.py container build master .

[stormi]

Side note, would it make sense to use master by default if no arg passed

I don't think so. Building for supported releases is equally important, better not try to guess what the developer/packager intends to do.

[rzr]

Side note, would it make sense to use master by default if no arg passed

I don't think so. Building for supported releases is equally important, better not try to guess what the developer/packager intends to do.

I removed this suggestion in commit message, and removed the conventional commit prefix, and added reviewers from merged PRs of this repo (which miss a codeowner for automatically add reviewers)

[stormi]

I'm having a hard time figuring out from the commit message what is the problem that we want to solve. I think it's adding support for master as an argument to build.sh, but it's not entirely clear from the text :)