is_tarfile accepts pathlike (#3804)

stdlib/2and3/tarfile.pyi

@@ -177,7 +177,10 @@ class TarFile(Iterable[TarInfo]):
                    fileobj: Optional[IO[bytes]] = ...) -> TarInfo: ...
     def close(self) -> None: ...
 
-def is_tarfile(name: str) -> bool: ...
+if sys.version_info >= (3, 9):
+    def is_tarfile(name: Union[_Path, IO[bytes]]) -> bool: ...
+else:
+    def is_tarfile(name: _Path) -> bool: ...
 
 if sys.version_info < (3, 8):
     def filemode(mode: int) -> str: ...  # undocumented