Add zizmor checks on CI. (#5161)

* Add zizmor checks on CI.

* Fix zizmor credentials warnings

* Add persist-credentials: false to action-cached-lfs-checkout too.

* Add empty permissions by default.

* Ignore pull_request_target failure and add a warning.

.github/workflows/danger.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
     types: [ labeled, synchronize, opened, reopened ]
 
+permissions: {}
+
 jobs:
   build:
     name: Danger
@@ -16,7 +18,10 @@ jobs:
       cancel-in-progress: true
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
       - name: Danger
         uses: danger/swift@434d7c25f3b02d490a340b23f5e78dd15a5670bc # 3.22.1
         env: