github: do not persist git creds beyond checkout in tests job

Signed-off-by: Simon Deziel <simon.deziel@canonical.com>

Author: simondeziel

.github/workflows/tests.yml

@@ -20,6 +20,8 @@ jobs:
     steps:
     - name: Repository checkout
       uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      with:
+        persist-credentials: false
 
     - name: Require GHA pinning
       uses: canonical/lxd/.github/actions/require-gha-pinning@main
@@ -54,6 +56,8 @@ jobs:
     steps:
     - name: Repository checkout
       uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      with:
+        persist-credentials: false
 
     - name: Install dependencies
       run: |
@@ -84,6 +88,8 @@ jobs:
     steps:
     - name: Repository checkout
       uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      with:
+        persist-credentials: false
 
     - name: Set up Python
       uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0