update from flask-graphql to graphql-server;

Author: chrisbc

nshm_model_graphql_api/nshm_model_graphql_api.py

@@ -7,7 +7,7 @@
 import yaml
 from flask import Flask
 from flask_cors import CORS
-from flask_graphql import GraphQLView
+from graphql_server.flask import GraphQLView
 
 # from nshm_model_graphql_api.library_version_check import log_library_info
 from nshm_model_graphql_api.schema import schema_root