Update labeler.yml (#705)

Fix right for labeling external PR

Author: rflamary

.github/workflows/labeler.yml

@@ -1,7 +1,7 @@
 name: "Pull Request Labeler"
 
 on:
-  pull_request:
+  pull_request_target:
     branches:
       - 'master'
 jobs:
@@ -11,4 +11,4 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/labeler@v5
+    - uses: actions/labeler@v5