tests: add placeholders for unlink/rmdir

Author: efiop

dvc_ssh/tests/cloud.py

@@ -59,6 +59,12 @@ def read_bytes(self):
         with self._ssh.open(self.path, "rb") as fobj:
             return fobj.read()
 
+    def unlink(self, missing_ok: bool = False) -> None:
+        raise NotImplementedError
+
+    def rmdir(self, recursive: bool = True) -> None:
+        raise NotImplementedError
+
     @property
     def fs_path(self):
         return self.path