Bump actions/setup-python from 2 to 4 (#900)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 2 to 4.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](https://github.com/actions/setup-python/compare/v2...v4)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/pykanidm_mypy.yml

@@ -11,7 +11,7 @@ jobs:
         with:
           fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod
       - name: Set up Python 3.9
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'
       - name: Running mypy

.github/workflows/pykanidm_pylint.yml

@@ -11,7 +11,7 @@ jobs:
         with:
           fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod
       - name: Set up Python 3.9
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'
       - name: Running tests

.github/workflows/pykanidm_pytest.yml

@@ -17,7 +17,7 @@ jobs:
         with:
           fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod
       - name: Set up Python ${{matrix.python_version}}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: ${{matrix.python_version}}
       - name: Running pytest