docs: fix typo in model.py

googleapiclient/model.py

diff --git a/googleapiclient/model.py b/googleapiclient/model.py
index 0449a92..554056e 100644
--- a/googleapiclient/model.py
+++ b/googleapiclient/model.py
@@ -342,7 +342,7 @@
     def __init__(self, protocol_buffer):
         """Constructs a ProtocolBufferModel.
 
-    The serialzed protocol buffer returned in an HTTP response will be
+    The serialized protocol buffer returned in an HTTP response will be
     de-serialized using the given protocol buffer class.
 
     Args: