Use v3 of checkout and python actions and cache pip

.github/workflows/build.yaml

@@ -13,7 +13,7 @@ jobs:
     # github change
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           # Need to clone everything for the git tags.
           fetch-depth: 0

.github/workflows/build_docs.yaml

@@ -10,15 +10,17 @@ jobs:
   build_sphinx_docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           # Need to clone everything for the git tags.
           fetch-depth: 0
 
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: 3.8
+          cache: "pip"
+          cache-dependency-path: "setup.cfg"
 
       - name: Update pip/wheel infrastructure
         run: |

.github/workflows/docstyle.yaml

@@ -10,12 +10,13 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - 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: 3.8
+          cache: "pip"
 
       - name: Install
         run: pip install pydocstyle

.github/workflows/formatting.yaml

@@ -11,12 +11,13 @@ jobs:
     runs-on: ubuntu-latest
     name: check Python formatting
     steps:
-      - 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: 3.8
+          cache: "pip"
 
       - name: Install isort and black
         run: pip install isort black

.github/workflows/lint.yaml

@@ -10,12 +10,13 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - 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: 3.8
+          cache: "pip"
 
       - name: Install
         run: pip install -r <(curl https://raw.githubusercontent.com/lsst/linting/main/requirements.txt)

.github/workflows/mypy.yaml

@@ -11,12 +11,13 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - 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: 3.8
+          cache: "pip"
 
       - name: Install
         run: pip install mypy