ci: Add mypy problem matcher

Author: khvn26

.github/workflows/api-pull-request.yml

@@ -67,7 +67,10 @@ jobs:
         run: make django-make-migrations
 
       - name: Check for new typing errors
-        run: make typecheck
+        uses: liskin/gh-problem-matcher-wrap@v2
+        with: 
+          linters: mypy
+          run: make typecheck
 
       - name: Check autogenerated documentation
         uses: nickcharlton/diff-check@v1.0.0