github: Sync test workflow with that of xmonad-contrib

.github/workflows/tests.yml

@@ -1,4 +1,4 @@
-name: Stack Tests
+name: Tests
 
 on:
     pull_request:
@@ -24,8 +24,9 @@ jobs:
         uses: actions/cache@v2
         with:
           path: ~/.stack
-          key: ${{ runner.os }}-${{ matrix.resolver }}-${{ hashFiles('stack.yaml') }}
+          key: ${{ runner.os }}-${{ matrix.resolver }}-${{ hashFiles('stack.yaml') }}-${{ hashFiles('xmonad.cabal') }}
           restore-keys: |
+            ${{ runner.os }}-${{ matrix.resolver }}-${{ hashFiles('stack.yaml') }}-
             ${{ runner.os }}-${{ matrix.resolver }}-
 
       - name: Build and run tests
@@ -36,4 +37,3 @@ jobs:
             sudo apt install -y libasound2 libasound2-dev libxrandr-dev libtinfo-dev
             sudo apt install -y libx11-dev libgmp-dev libxss-dev libxft-dev
             stack test --fast --no-terminal --resolver=${{ matrix.resolver }}
-

stack.yaml

@@ -1,7 +1,7 @@
 resolver: lts-16.22
 
 packages:
-  - ./
+- ./
 
 extra-deps:
 - X11-1.9.2