Fix build errors: Update deprecated GitHub Actions versions

Author: micahgallen

.github/workflows/docs.yml

@@ -18,7 +18,7 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Set up Python 3.9
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v4
         with:
           python-version: 3.9
 

.github/workflows/linting.yml

@@ -9,12 +9,12 @@ jobs:
       matrix:
         python-version: [3.8]
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
-    - uses: actions/cache@v2
+    - uses: actions/cache@v4
       name: Configure pip caching
       with:
         path: ~/.cache/pip