Bump setup-python

Author: David Rubinstein

.github/workflows/tox.yml

@@ -22,7 +22,7 @@ jobs:
           - "3.7"
     steps:
       - name: Setup python for test ${{ matrix.py }}
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.py }}
       - uses: actions/checkout@v3