Add missing Issue/PR attribution for #1564

Including: #1708

CHANGELOG.md

@@ -43,15 +43,15 @@ By [@o0Ignition0o](https://github.com/o0Ignition0o) in https://github.com/apollo
 
 ## 🚀 Features
 
-### New plugin helper: `map_first_graphql_response`
+### New plugin helper: `map_first_graphql_response` ([Issue #1564](https://github.com/apollographql/router/issues/1564))
 
 In supergraph and execution services, the service response contains not just one GraphQL response but a stream of them, in order to support features such as `@defer`.
 
 This new method of `ServiceExt` and `ServiceBuilderExt` in `apollo_router::layers` wraps a service and calls a `callback` when the first GraphQL response in the stream returned by the inner service becomes available.  The callback can then access the HTTP parts (headers, status code, etc) or the first GraphQL response before returning them.
 
 See the doc-comments in `apollo-router/src/layers/mod.rs` for more.
 
-By [@SimonSapin](https://github.com/SimonSapin)
+By [@SimonSapin](https://github.com/SimonSapin) in https://github.com/apollographql/router/pull/1708
 
 ### Users can customize the Prometheus listener address and URL path ([Issue #1645](https://github.com/apollographql/router/issues/1645))