use pull_reqeust_target event (#569)

Author: jimmyjames

.github/workflows/snyk.yml

@@ -3,7 +3,7 @@ name: Snyk
 on:
   merge_group:
   workflow_dispatch:
-  pull_request:
+  pull_request_target:
     types:
       - opened
       - synchronize
@@ -23,7 +23,7 @@ concurrency:
 jobs:
   authorize:
     name: Authorize
-    environment: ${{ github.actor != 'dependabot[bot]' && github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name != github.repository && 'external' || 'internal' }}
+    environment: ${{ github.actor != 'dependabot[bot]' && github.event_name == 'pull_request_target' && github.event.pull_request.head.repo.full_name != github.repository && 'external' || 'internal' }}
     runs-on: ubuntu-latest
     steps:
       - run: true