cache dependencies

.github/workflows/test.yml

@@ -16,6 +16,22 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Get yarn cache directory path
+      id: yarn-cache-dir-path
+      run: echo "::set-output name=dir::$(yarn cache dir)"
+
+    - uses: actions/cache@v2
+      id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
+      with:
+        path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
+        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-yarn-
+
+    - name: Install dependencies
+      run: yarn
+      env:
+        NODE_ENV: development
     - uses: ./
       with: 
         reportIgnoredFiles: true