Fix mypy GitHub Action to directly call mypy

Author: tleonhardt

.github/workflows/mypy.yml

@@ -19,5 +19,5 @@ jobs:
           # Only a single commit is fetched by default, for the ref/SHA that triggered the workflow.
           # Set fetch-depth: 0 to fetch all history for all branches and tags.
           fetch-depth: 0 # Needed for setuptools_scm to work correctly
-      - run: pip install -U --user pip setuptools setuptools-scm nox
-      - run: python -m nox --non-interactive --session validate-3.13 -k mypy  # Run nox for mypy
+      - run: pip install -U --user pip mypy
+      - run: mypy .

noxfile.py

@@ -39,10 +39,3 @@ def tests(session, plugin):
             '--no-pty',
             '--append-cov',
         )
-
-
-@nox.session(python=['3.8', '3.9', '3.10', '3.11', '3.12', '3.13'])
-@nox.parametrize('step', ['mypy', 'flake8'])
-def validate(session, step):
-    session.install('invoke', './[validate]')
-    session.run('invoke', step)