Avoid using pull_request_target

Move to using `pull_request` and a permissions block.

.github/workflows/update-dependencies.yml

@@ -1,8 +1,12 @@
 name: Update dependencies
 on:
-  pull_request_target:
+  pull_request:
     types: [opened, synchronize, reopened, ready_for_review, labeled]
 
+permissions:
+  issues: write
+  contents: write
+
 jobs:
   update:
     name: Update dependencies