Update actions/cache action to v2 (#30)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

.github/workflows/build.yml

@@ -14,7 +14,7 @@ jobs:
           node-version: 12.x
 
       - name: Use cached node_modules
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         with:
           path: node_modules
           key: nodeModules-${{ hashFiles('**/yarn.lock') }}