remove Optional keyword

src/aiida/cmdline/utils/decorators.py

@@ -19,7 +19,6 @@
 """
 
 from contextlib import contextmanager
-from typing import Optional
 
 from click_spinner import spinner
 from packaging.version import Version
@@ -241,7 +240,7 @@ def do_circus_stuff():
     return wrapped(*args, **kwargs)
 
 
-def deprecated_command(message: str, version: Optional[str] = '3.0.0'):
+def deprecated_command(message: str, version: str = '3.0.0'):
     """Function decorator that will mark a click command as deprecated when invoked.
 
     :param message: The message that should be printed with the deprecation warning.