update github action config

Author: tchak

.github/workflows/ci.yml

@@ -3,20 +3,28 @@ on: [push]
 jobs:
   run:
     name: Run
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        os: [ubuntu-latest]
+    runs-on: ubuntu-latest
+
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v2
+      with:
+        node-version: '14'
+
+    - name: Get yarn cache directory path
+      id: yarn-cache-dir-path
+      run: echo "::set-output name=dir::$(yarn cache dir)"
 
-    - name: Set Node.js 12.x
-      uses: actions/setup-node@v1
+    - uses: actions/cache@v2
+      id: yarn-cache
       with:
-        version: 12.x
+        path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
+        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-yarn-
 
     - name: Install
-      run: yarn install
+      run: yarn install --frozen-lockfile --non-interactive
 
     - name: Lint
       run: yarn lint