Add delete filter parsing to grpc_index

Author: benjaminran

pinecone/core/grpc/index_grpc.py

@@ -259,7 +259,8 @@ def _vector_transform(item):
             return self._wrap_grpc_call(self.stub.Upsert, request, timeout=timeout)
 
     def delete(self, *args, async_req=False, **kwargs):
-        request = DeleteRequest(*args, **kwargs)
+        _filter = dict_to_proto_struct(kwargs.pop('filter', None))
+        request = DeleteRequest(*args, **kwargs, filter=_filter)
         timeout = kwargs.pop('timeout', None)
         if async_req:
             future = self._wrap_grpc_call(self.stub.Delete.future, request, timeout=timeout)