Allow only verified mounted checkout for patch Git show

patch_runtime.py

@@ -12,7 +12,7 @@ for relative_path in (
     "app.py",
 ):
     pristine = subprocess.check_output(
-        ["git", "-C", "app", "show", f"HEAD:{relative_path}"]
+        ["git", "-c", "safe.directory=/data/app", "-C", "app", "show", f"HEAD:{relative_path}"]
     )
     Path("app", relative_path).write_bytes(pristine)