Bump actions/setup-python from 2 to 4

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

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/promote.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Install python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
 
       - name: Install dependencies
         run: |

.github/workflows/pull_request.yml

@@ -28,7 +28,7 @@ jobs:
           fetch-depth: 0
 
       - name: Setup up python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
 
       - name: Install tox
         run: pip install tox
@@ -122,7 +122,7 @@ jobs:
         run: sudo chmod a+x /usr/local/bin/receptor
 
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
 
@@ -141,7 +141,7 @@ jobs:
           fetch-depth: 0
 
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
 
       - name: Install python dependencies
         run: pip install build

.github/workflows/stage.yml

@@ -44,7 +44,7 @@ jobs:
           ref: ${{ github.event.inputs.ref }}
 
       - name: Install python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
 
       - name: Install dependencies
         run: |