[mypy_primer] run using 3.10 (#11798)

Co-authored-by: hauntsaninja <>

.github/workflows/mypy_primer.yml

@@ -26,7 +26,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-python@v2
         with:
-          python-version: 3.8
+          python-version: "3.10"
       - name: Install dependencies
         run: |
           python -m pip install -U pip