Upgrade GraphQL Dependency to allow v15, v16

[sternma]

GraphQL versions 15 and 16 are currently not supported in the dependencies. Opening this issue to upgrade the dependencies.

[ransfordarthurjr]

try Graphql Scalars https://the-guild.dev/graphql/scalars/docs

seems like the project is not in active development, at least there's not been any update in years

[gustawdaniel]

It works:

npm install graphql-scalars

and

import { GraphQLDateTime } from 'graphql-scalars';