Allow multiple release branches for the goals release-start and release-finish

[jelingi]

Hi Alex,

I'm suggesting the implementation for the feature to allow multiple release branches. This becomes essential when support branches cannot be utilized. In our scenario, we are consistently developing for mulitple different versions concurrently. We've thoroughly tested the solution across various cases, and it has proven effective. We believe it would benefit many other users of the plugin, evident from the numerous requests for this feature.

To implement this feature, we made changes to the release-start and release-finish goals:

1. release-start: Added the parameter allowMultipleReleaseBranches. When set to true, a new release branch is created even if there's already an existing one in the remote repository.
2. release-finish: Added the parameter releaseBranchName. With this parameter, you can specify the release branch you want to proceed with. If this parameter is empty and there is only one existing release branch in your remote repository, that branch is used. Otherwise, an exception is thrown.

We welcome any feedback on these changes.

Thanks and kind regards,
Jelin

[robert2411]

Any progress on this? It would also be usefull for some of the projects I work on