workflows/tests: fix artipacked zizmor findings

We don't need persistent credentials here.

.github/workflows/tests.yml

@@ -15,6 +15,8 @@ jobs:
     steps:
       - name: Set up Git repository
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          persist-credentials: false
 
       - name: Set up Homebrew
         id: set-up-homebrew