ci: cache node_modules (#6048)

Author: GeopJr

.github/workflows/ci.yml

@@ -13,6 +13,14 @@ jobs:
     - uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
+    - id: npm-cache-dir
+      run: echo "::set-output name=dir::$(npm config get cache)"
+    - uses: actions/cache@v2
+      id: npm-cache
+      with:
+        path: ${{ steps.npm-cache-dir.outputs.dir }}
+        key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: ${{ runner.os }}-node-
     - run: npm install
     - run: npm test
       env:
@@ -23,6 +31,14 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - uses: actions/setup-node@v1
+    - id: npm-cache-dir
+      run: echo "::set-output name=dir::$(npm config get cache)"
+    - uses: actions/cache@v2
+      id: npm-cache
+      with:
+        path: ${{ steps.npm-cache-dir.outputs.dir }}
+        key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: ${{ runner.os }}-node-
     - run: 'npm i && npm run lint'
   Unit:
     runs-on: ${{ matrix.os }}
@@ -33,4 +49,12 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - uses: actions/setup-node@v1
+    - id: npm-cache-dir
+      run: echo "::set-output name=dir::$(npm config get cache)"
+    - uses: actions/cache@v2
+      id: npm-cache
+      with:
+        path: ${{ steps.npm-cache-dir.outputs.dir }}
+        key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: ${{ runner.os }}-node-
     - run: 'npm i && npm run test:unit'