Issue with branch names when using git tag

The issue is that this plugin creates a hash file name based on branch name and mount path and every time you git tag you will have new cache file. DRONE_BRANCH and DRONE_TAG are the same at least for bitbucket.org. I saw the commented code that handles fallback when there is no cache file it takes from master by default and that is as a DRONE_REPO_BRANCH.
So my question is can we handle this situation by using DRONE_REPO_BRANCH value as fallback?

Start by locating the code that builds cache file names from the branch name and mount path, then inspect the commented fallback used when no cache file exists. Reproduce the behavior with a tagged build and compare DRONE_BRANCH, DRONE_TAG, and DRONE_REPO_BRANCH. Done means tagged builds consistently use the repository branch fallback without creating a new cache file per tag.

Written by the indexing model from the issue text.