[BUG] All release tags are created on master

[Aytackydln]

I want my dev branch to make prereleases but it still creates the release tags on master. This step should specify branch or commit while releasing.

target_commitish needs to be specified while making release. This can be an optional parameter, too.

[illusion0001]

I think this is what #46 is solving, but it has not been merged yet

[Hiroshiba]

I faced the same issue. The proposed pull request does indeed seem to solve this issue. I hope you merge it! @svenstaro