Merge pull request #7 from spotify/fix-frontend-ci

chore: fix ci setup and cache node modules

.github/workflows/frontend.yml

@@ -4,6 +4,7 @@ on:
   push:
     paths:
     - 'frontend/**'
+    - '.github/**'
 
 jobs:
   build:
@@ -14,11 +15,21 @@ jobs:
         node-version: [12.x]
 
     steps:
-    - uses: actions/checkout@v1
+    - name: checkout code
+      uses: actions/checkout@v1
+    - name: get yarn cache
+      id: yarn-cache
+      run: echo "::set-output name=dir::$(yarn cache dir)"
+    - uses: actions/cache@v1
+      with:
+        path: ${{ steps.yarn-cache.outputs.dir }}
+        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-yarn-
     - name: use node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v1
-      working-directory: ./frontend
       with:
+        working-directory: ./frontend
         node-version: ${{ matrix.node-version }}
     - name: yarn install, build, and test
       working-directory: ./frontend

frontend/.yarnrc

@@ -4,3 +4,4 @@
 
 lastUpdateCheck 1580389148099
 yarn-path ".yarn/releases/yarn-1.21.1.js"
+registry "https://registry.npmjs.org/"