Feature: Add alternative base branches

[jeppekroghitk]

I ran into a project where "main" were the main branch. Since "develop" is the only predefined base branch, the release script did not work. I added an array of base branches, defined as ["develop", "main", "master"], to increase the success rate of the release script.

Apologies in advance - AI aided me with these changes, as i have yet to learn GO.

• Updated baseBranch from string to array of strings
• Updated release script to handle array of base branches and try each one

[rimi-itk]

Great idea!

We need to make sure that users can (also) override the base branch, so something along the lines of

	baseBranch string = func() string {
		branches := []string{"develop", "main", "master"}
		for _, branch := range branches {
			cmd := exec.Command("git", "rev-parse", "--verify", "-b", branch)
			if _, err := cmd.CombinedOutput(); err == nil {
				return branch
			}
		}

		// Fallback if no other suitable branch is found.
		return branches[0]
	}()

may be a better approach, i.e. digging for a sane default branch.

[jeppekroghitk]

@rimi-itk Donno