Bumped versions in Github actions configuration to v3.

.github/workflows/docs.yml

@@ -4,11 +4,13 @@ on:
   pull_request:
     paths:
       - 'docs/**'
+      - '.github/workflows/docs.yml'
   push:
     branches:
       - main
     paths:
       - 'docs/**'
+      - '.github/workflows/docs.yml'
 
 jobs:
   docs:
@@ -17,18 +19,13 @@ jobs:
     name: docs
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: '3.10'
-      - name: Cache dependencies
-        uses: actions/cache@v2
-        with:
-          path: ~/.cache/pip
-          key: ${{ runner.os }}-pip-${{ hashFiles('docs/requirements.txt') }}
-          restore-keys: |
-            ${{ runner.os }}-pip-
+          cache: 'pip'
+          cache-dependency-path: 'docs/requirements.txt'
       - run: python -m pip install -r docs/requirements.txt
       - name: Build docs
         run: |