Update ci.yml

Author: wellyshen

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
       - name: Get cached node modules
         id: yarn-cache-dir-path
         run: echo "::set-output name=dir::$(yarn cache dir)"
-      - uses: actions/cache@v2.1.6
+      - uses: actions/cache@v2
         id: yarn-cache
         with:
           path: ${{ steps.yarn-cache-dir-path.outputs.dir }}