fix: update broken graphql spec link (graphql#1410)

Author: CSalih

src/content/learn/BestPractice-ServingOverHTTP.md

@@ -69,7 +69,7 @@ Regardless of the method by which the query and variables were sent, the respons
 }
 ```
 
-If there were no errors returned, the `"errors"` field should not be present on the response. If no data is returned, [according to the GraphQL spec](http://facebook.github.io/graphql/#sec-Data), the `"data"` field should only be included if no errors occurred during execution.
+If there were no errors returned, the `"errors"` field should not be present on the response. If no data is returned, [according to the GraphQL spec](https://spec.graphql.org/October2021/#sec-Data), the `"data"` field should only be included if no errors occurred during execution.
 
 ## GraphiQL
 GraphiQL is useful during testing and development but should be disabled in production by default. If you are using express-graphql, you can toggle it based on the NODE_ENV environment variable:
@@ -87,4 +87,4 @@ If you are using NodeJS, we recommend looking at the [list of server implementat
 
 ## Draft Transport Specification
 
-A detailed [HTTP & websockets transport specification](https://github.com/graphql/graphql-over-http) is in development. Though it is not yet finalized, these draft specifications act as a single source of truth for GraphQL client & library maintainers, detailing how to expose and consume a GraphQL API using an HTTP transport. Unlike the language specification, adherence is not mandatory, but most implementations are moving towards these standards to maximize interoperability.
+A detailed [HTTP & websockets transport specification](https://github.com/graphql/graphql-over-http) is in development. Though it is not yet finalized, these draft specifications act as a single source of truth for GraphQL client & library maintainers, detailing how to expose and consume a GraphQL API using an HTTP transport. Unlike the language specification, adherence is not mandatory, but most implementations are moving towards these standards to maximize interoperability.