Update branch name extraction for tag builds (#608)

* Remove leading whitespace from branch name in workflow for tag build

* Filter branches and specify format when using git branch in workflow

.github/workflows/ci.yml

@@ -43,8 +43,7 @@ jobs:
           branch=main
           if [[ $ref_type == "tag"* ]]
           then
-            raw=$(git branch -r --contains ${{ github.ref_name }})
-            branch=${raw/origin\/}
+            branch=$(git branch -r --contains ${{ github.ref_name }} --list '*release*' --format "%(refname:short)" | sed -e 's/^origin\///')
           fi
           tox -e test-cpu -- $branch
       - name: Generate package for pypi