CI: Add dependency package caching per GHA's actions/setup-python

Author: amotl

.github/workflows/docs.yml

@@ -23,6 +23,8 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: '3.9'
+          cache: 'pip'
+          cache-dependency-path: 'setup.py'
 
       - name: Build docs
         run: |

.github/workflows/nightly.yml

@@ -30,6 +30,8 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+          cache: 'pip'
+          cache-dependency-path: 'setup.py'
 
       - name: Invoke tests
         run: |

.github/workflows/release.yml

@@ -15,6 +15,8 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: '3.9'
+          cache: 'pip'
+          cache-dependency-path: 'setup.py'
 
       - name: Build package
         run: |

.github/workflows/tests.yml

@@ -31,6 +31,8 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+          cache: 'pip'
+          cache-dependency-path: 'setup.py'
 
       - name: Invoke tests
         run: |