Bump actions/setup-python from 3 to 4 (#16)

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -12,7 +12,7 @@ jobs:
       - uses: actions/checkout@v3
 
       - name: Setup Python
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v4
         with:
           python-version: "3.8"
 

.github/workflows/publish.yml

@@ -11,7 +11,7 @@ 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

.github/workflows/tests.yml

@@ -15,7 +15,7 @@ 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 }}
       - name: Install dependencies