Update setup-python

v2 failed because it interpreted 3.10 to be 3.1

Author: bnmnetp

.github/workflows/python-app.yml

@@ -22,9 +22,9 @@ jobs:
                 with:
                     path: RunestoneServer
             -   name: Set up Python 3.10
-                uses: actions/setup-python@v2
+                uses: actions/setup-python@v4
                 with:
-                    python-version: 3.10
+                    python-version: '3.10'
             -   name: Build container
                 id: docker-build
                 run: |