Update build-test.yml (#13)

.github/workflows/build-test.yml

@@ -4,7 +4,10 @@ on:
     branches: [ "master" ]
   pull_request:
     branches: [ "master" ]
-
+  pull_request_target:
+    types: [labeled]
+    branches: [ "master" ]
+
   workflow_dispatch:
 
 jobs:
@@ -14,8 +17,16 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+    - name: Checkout Code
+      if: github.event_name == 'pull_request_target' || contains(github.event.pull_request.labels.*.name, 'safe to test')
+      uses: actions/checkout@v3
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
+
+    - name: Checkout Code for Push
+      if: github.event_name == 'push' || github.event_name == 'pull_request'
+      uses: actions/checkout@v3
 
-    - uses: actions/checkout@v3
     - name: Set up Python 3.9
       uses: actions/setup-python@v3
       with: