Workaround for mypy complaining about the cache

Related to issue: python/mypy#10768

Author: jmichelp

.github/workflows/mypy.yml

@@ -26,4 +26,5 @@ jobs:
         run: echo ::add-matcher::./.github/python_matcher.json
       - name: Running mypy
         run: |
+          mkdir -p .mypy_cache
           mypy --no-color-output --install-types --non-interactive scaaml tests