Don't persist GitHub credentials after checkout

Fixes potential issue found by zizmor: https://github.com/woodruffw/zizmor

Author: tomkins

source/guides/github-actions-ci-cd-sample/publish-to-test-pypi.yml

@@ -9,6 +9,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
+      with:
+        persist-credentials: false
     - name: Set up Python
       uses: actions/setup-python@v5
       with: