Flask-GraphQL now returns warnings when using `graphql-core

Now that the minimum version of graphql-core was bumped to >=2.3 we're now seeing warnings returning when running tests that leverage Flask-GraphQL.

Here's the relevant diff between graphql-core 2.2.1 and 2.3:
graphql-python/graphql-core@v2.2.1...v2.3.0#diff-a2c439ae03cccc507934c1377530d14aL74-L87

In graphqlview.py - arguments are being passed as root and context though it seems these arguments are getting deprecated in favor of root_value and context_value.

flask-graphql/flask_graphql/graphqlview.py

Lines 92 to 93 in 0137ca1

    
           root=self.get_root_value(), 
        
           context=self.get_context(),

Here's the relevant DeprecationWarning

DeprecationWarning: The 'context' alias has been deprecated. Please use 'context_value' instead.
DeprecationWarning: The 'root' alias has been deprecated. Please use 'root_value' instead.

Yes, the "_value" prefix has been added back in Core 2.3, to make the API consistent with GraphQL.js and Core 3 again. So this should be changed in Flask-GraphQL as well to remove the warnings.

This only requires changes on the provided execute options in flask according to the executor. graphql-core diff 2.2.1 - 2.3 and bumping the minimum graphql-core version at setup.py, right?

Yes. Of course it would be also great to have a flask-graphql v3 based on graphql-core v3.