fix: use GITHUB_REF as part of cache key for pip

Author: Jim-Holmstroem

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
         # This path is specific to Ubuntu
         path: ~/.cache/pip
         # Look to see if there is a cache hit for the corresponding requirements file
-        key: ${{ runner.os }}-python${{ matrix.python-version}}-pip-${{ hashFiles('requirements.txt') }}-${{ hashFiles('dev_requirements.txt') }}
+        key: ${{ runner.os }}-python${{ matrix.python-version}}-pip-${{ hashFiles('requirements.txt') }}-${{ hashFiles('dev_requirements.txt') }}-${ GITHUB_REF }
 
     - name: Patch for Python 3.6
       if: matrix.python-version == 3.6