fix： share github secrets to dependabot (#712)

Author: chenxuan-zhou

.github/workflows/node.js.yml

@@ -8,6 +8,8 @@ on:
     branches: [ dev, master ]
   pull_request:
     branches: [ dev, master ]
+  pull_request_target:
+    branches: [ dev, master ]
 
 jobs:
   build:
@@ -24,8 +26,21 @@ jobs:
         node-version: [14.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
 
+    if: |
+      (github.event_name == 'pull_request_target' && github.actor == 'dependabot[bot]') ||
+      (github.event_name != 'pull_request_target' && github.actor != 'dependabot[bot]')
+
     steps:
-    - uses: actions/checkout@v2
+    - name: Checkout
+      if: ${{ github.event_name != 'pull_request_target' }}
+      uses: actions/checkout@v2
+
+    - name: Checkout PR
+      if: ${{ github.event_name == 'pull_request_target' }}
+      uses: actions/checkout@v2
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
+        
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v2
       with: