squash: use key_to_option function

Author: therazix

tmt/config/models/__init__.py

@@ -1,13 +1,10 @@
 from tmt._compat.pydantic import BaseModel, Extra
-
-
-def create_alias(name: str) -> str:
-    return name.replace('_', '-')
+from tmt.utils import key_to_option
 
 
 class BaseConfig(BaseModel):
     class Config:
         # Accept only keys with dashes instead of underscores
-        alias_generator = create_alias
+        alias_generator = key_to_option
         extra = Extra.forbid
         validate_assignment = True