fix python version and pytest install

.github/workflows/pull_request.yml

@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v4
         with:
-          python-version: 3.10
+          python-version: "3.10.14"
           cache: "pip"
           cache-dependency-path: "**/requirements*.txt"
       # Need the right version of clang-format
@@ -45,5 +45,7 @@ jobs:
       - uses: actions/checkout@v2
       - name: prepare data
         run: python prepare_data.py
+      - name: install pytest
+        run: pip install pytest
       - name: Run Tests
         run: pytest --forked tests