CI: Update to actions/setup-python@v4

Author: amotl

.github/workflows/docs.yml

@@ -20,7 +20,7 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Set up Python
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'
 

.github/workflows/nightly.yml

@@ -24,7 +24,7 @@ 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 }}
 

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v3
 
       - name: Set up Python
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: '3.9'
 

.github/workflows/tests.yml

@@ -25,7 +25,7 @@ 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 }}