chore: Update mypy.yml python version in owlbot.py

Author: chalmerlowe

owlbot.py

@@ -258,4 +258,12 @@ def lint_setup_py(session):
 ''',
 )
 
+\
+# Ensure mypy.yml uses the default Python version
+s.replace(
+    ".github/workflows/mypy.yml",
+    r"python-version: ['3.8']",
+    "python-version: ['3.10']"
+)
+
 s.shell.run(["nox", "-s", "blacken"], hide_output=False)