When using a branch name which contains forward slashes ("/") in it (e.g. "feature/my-feature"), docker-compose based pipelines using Jenkins `BUILD_TAG` as the project name fail to build. This happens because slashes in the branch name get incorrectly url-encoded into "%2F" for the `JOB_NAME` variable, which in turns is used to create the `BUILD_TAG` variable. These encoded characters are passed in the docker-compose command option, which doesn't accept the "%" character, and this breaks the build.

`BUILD_TAG` already takes care of replacing possible forward slashes with dashes ("-"), so it's not `BUILD_TAG` at fault here. Clearly, it's also not docker-compse at fault for not accepting special characters.

The Bitbucket Source Plugin plugin, when assembling the `JOB_NAME` variable from the branch name, should simply preserve the slashes, according to the Pipeline Syntax:

and that would be sufficient to unbreak the building of branches with slashes in their name.