build: pip cache works again

Author: nedbat

.github/workflows/coverage.yml

@@ -59,8 +59,8 @@ jobs:
         uses: "actions/setup-python@v2"
         with:
           python-version: "${{ matrix.python-version }}"
-          #cache: pip
-          #cache-dependency-path: 'requirements/*.pip'
+          cache: pip
+          cache-dependency-path: 'requirements/*.pip'
 
       - name: "Install dependencies"
         run: |
@@ -96,8 +96,8 @@ jobs:
         uses: "actions/setup-python@v2"
         with:
           python-version: "3.8"
-          #cache: pip
-          #cache-dependency-path: 'requirements/*.pip'
+          cache: pip
+          cache-dependency-path: 'requirements/*.pip'
 
       - name: "Install dependencies"
         run: |

.github/workflows/testsuite.yml

@@ -55,8 +55,9 @@ jobs:
         uses: "actions/setup-python@v2"
         with:
           python-version: "${{ matrix.python-version }}"
-          #cache: pip
-          #cache-dependency-path: 'requirements/*.pip'
+          # Can we start using the pip cache again?
+          cache: pip
+          cache-dependency-path: 'requirements/*.pip'
 
       - name: "Install dependencies"
         run: |