Add attributes field in Project model (as read only) (#151)

Note: This should be expanded upon to include add/remove operations https://snyk.docs.apiary.io/#reference/projects/project-attributes/applying-attributes

snyk/models.py

@@ -569,6 +569,7 @@ class Project(DataClassJSONMixin):
     hostname: Optional[str] = None
     remoteRepoUrl: Optional[str] = None
     branch: Optional[str] = None
+    attributes: Optional[Dict[str, List[str]]] = None
     _tags: Optional[List[Any]] = field(default_factory=list)
 
     def delete(self) -> bool: