fix(relations): replace the model type TypeVar with Any

Ref #168

rest_framework-stubs/relations.pyi

@@ -71,9 +71,9 @@ class RelatedField(Field[_MT, Any, _PT, Any]):
     def iter_options(self) -> Iterable[Option]: ...
     def display_value(self, instance: _MT) -> str: ...
 
-class StringRelatedField(RelatedField[_MT, str]): ...
+class StringRelatedField(RelatedField[Any, str]): ...
 
-class PrimaryKeyRelatedField(RelatedField[_MT, Any]):
+class PrimaryKeyRelatedField(RelatedField[Any, Any]):
     pk_field: str | None
     def __init__(
         self,
@@ -98,7 +98,7 @@ class PrimaryKeyRelatedField(RelatedField[_MT, Any]):
         pk_field: str | Field | None = ...,
     ) -> None: ...
 
-class HyperlinkedRelatedField(RelatedField[_MT, Hyperlink]):
+class HyperlinkedRelatedField(RelatedField[Any, Hyperlink]):
     reverse: Callable
     lookup_field: str
     lookup_url_kwarg: str
@@ -134,7 +134,7 @@ class HyperlinkedRelatedField(RelatedField[_MT, Hyperlink]):
 
 class HyperlinkedIdentityField(HyperlinkedRelatedField): ...
 
-class SlugRelatedField(RelatedField[_MT, str]):
+class SlugRelatedField(RelatedField[Any, str]):
     slug_field: str | None
     def __init__(
         self,