fix: fix bad common prefix (#115)

https://github.com/LedgerHQ/clear-signing-erc7730-registry/actions/runs/11482854454/job/31956915855?pr=22#step:7:152

see https://stackoverflow.com/questions/21498939/how-to-circumvent-the-fallacy-of-pythons-os-path-commonprefix

src/erc7730/lint/lint.py

@@ -67,7 +67,7 @@ def get_descriptor_files() -> Generator[Path, None, None]:
 
     files = list(get_descriptor_files())
 
-    if len(files) <= 1 or not (root_path := os.path.commonprefix(files)):
+    if len(files) <= 1 or not (root_path := os.path.commonpath(files)):
         root_path = None
 
     def label(f: Path) -> Path | None: