Update main.yml

Fix reference to package-lock.json

.github/workflows/main.yml

@@ -25,7 +25,7 @@ jobs:
         uses: actions/cache@v1
         with:
           path: ~/.npm
-          key: ${{ runner.os }}-node-${{ hashFiles('**/npm-shrinkwrap.json') }}-${{ matrix.node-version }}
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}-${{ matrix.node-version }}
 
       - name: Install
         run: npm install