fix(ci): fix mypy invocation

Author: nijel

.github/workflows/mypy.yml

@@ -39,5 +39,5 @@ jobs:
     - name: Run mypy
       run: |
         echo "::add-matcher::.github/matchers/mypy.json"
-        mypy --show-column-numbers weblate_web
+        mypy --show-column-numbers weblate_language_data
         echo "::remove-matcher owner=mypy::"