Add CHANGELOG for #3894.

CHANGELOG.md

@@ -5,6 +5,10 @@ The version headers in this history reflect the versions of Apollo Server itself
 - [__CHANGELOG for `@apollo/gateway`__](https://github.com/apollographql/apollo-server/blob/master/packages/apollo-gateway/CHANGELOG.md)
 - [__CHANGELOG for `@apollo/federation`__](https://github.com/apollographql/apollo-server/blob/master/packages/apollo-federation/CHANGELOG.md)
 
+### v2.13.0
+
+- `apollo-server-core`: Support providing a custom logger implementation (e.g. [`winston`](https://npm.im/winston), [`bunyan`](https://npm.im/bunyan), etc.) to capture server console messages.  Though there has historically been limited output from Apollo Server, some messages are important to capture in the larger context of production logging facilities or can benefit from using more advanced structure, like JSON-based logging.  This also introduces a `logger` property to the `GraphQLRequestContext` that is exposed to plugins, making it possible for plugins to leverage the same server-level logger, and allowing implementors to create request-specific log contexts, if desired.  When not provided, these will still output to `console`. [PR #3894](https://github.com/apollographql/apollo-server/pull/3894)
+
 ### v2.12.0
 
 - `apollo-server-core`: When operating in gateway mode using the `gateway` property of the Apollo Server constructor options, the failure to initialize a schema during initial start-up, e.g. connectivity problems, will no longer result in the federated executor from being assigned when the schema eventually becomes available.  This precludes a state where the gateway may never become available to serve federated requests, even when failure conditions are no longer present. [PR #3811](https://github.com/apollographql/apollo-server/pull/3811)

packages/apollo-gateway/CHANGELOG.md

@@ -7,6 +7,7 @@
 - General improvements and clarity to error messages and logging. [PR #3811](https://github.com/apollographql/apollo-server/pull/3811)
 - Warn of a possible misconfiguration when local service configuration is provided (via `serviceList` or `localServiceList`) and a remote Apollo Graph Manager configuration is subsequently found as well. [PR #3868](https://github.com/apollographql/apollo-server/pull/3868)
 - During composition, the unavailability of a downstream service in unmanaged federation mode will no longer result in a partially composed schema which merely lacks the types provided by the downed service.  This prevents unexpected validation errors for clients querying a graph which lacks types which were merely unavailable during the initial composition but were intended to be part of the graph. [PR #3867](https://github.com/apollographql/apollo-server/pull/3867)
+- Support providing a custom logger implementation (e.g. [`winston`](https://npm.im/winston), [`bunyan`](https://npm.im/bunyan), etc.) to capture gateway-sourced console output.  This allows the use of existing, production logging facilities or the possibiltiy to use advanced structure in logging, such as console output which is encapsulated in JSON.  The same PR that introduces this support also introduces a `logger` property to the `GraphQLRequestContext` that is exposed to `GraphQLDataSource`s and Apollo Server plugins, making it possible to attach additional properties (as supported by the logger implementation) to specific requests, if desired, by leveraging custom implementations in those components respectively.  When not provided, these will still output to `console`. [PR #3894](https://github.com/apollographql/apollo-server/pull/3894)
 
 ## 0.13.2