ci(dependabot): bump actions/setup-python from 3 to 4 (#420)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 3 to 4.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v3...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/deploy_docs.yml

@@ -17,7 +17,7 @@ jobs:
 
       # Install dependencies
       - name: Set up Python 3.9
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: 3.9
       - name: Install Libraries

.github/workflows/test_and_deploy.yml

@@ -41,7 +41,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
       - uses: tlambert03/setup-qt-libs@v1
@@ -74,7 +74,7 @@ jobs:
           repository: napari/napari
           path: napari-from-github
       - uses: tlambert03/setup-qt-libs@v1
-      - uses: actions/setup-python@v3
+      - uses: actions/setup-python@v4
         with:
           python-version: '3.9'
       - name: Install
@@ -99,7 +99,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: "3.x"
       - name: Install dependencies