ci: fetch history for provenance tests

Author: magnaprog

.github/workflows/ci.yml

@@ -19,6 +19,10 @@ jobs:
         python-version: ["3.11", "3.12", "3.13", "3.14"]
     steps:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        with:
+          # Provenance tests verify that generated artifacts reference an
+          # ancestor source commit, which is unavailable in a depth-1 clone.
+          fetch-depth: 0
 
       - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with: