CHANGELOG: fix incorrect number

CHANGELOG.md

@@ -11,7 +11,7 @@ The version headers in this history reflect the versions of Apollo Server itself
 
 > The changes noted within this `vNEXT` section have not been released yet.  New PRs and commits which introduce changes should include an entry in this `vNEXT` section as part of their development.  With few exceptions, the format of the entry should follow convention (i.e., prefix with package name, use markdown `backtick formatting` for package names and code, suffix with a link to the change-set à la `[PR #YYY](https://link/pull/YYY)`, etc.).  When a release is being prepared, a new header will be (manually) created below and the appropriate changes within that release will be moved into the new section.
 
-## v2.22.2
+## v2.21.2
 
 - `apollo-server-core`: The `SIGINT` and `SIGTERM` signal handlers installed by default (when not disabled by `stopOnTerminationSignals: false`) now stay active (preventing process termination) while the server shuts down, instead of letting a second signal terminate the process. The handlers still re-signal the process after `this.stop()` concludes. Also, if `this.stop()` throws, the signal handlers will now log and exit 1 instead of throwing an uncaught exception. [Issue #4931](https://github.com/apollographql/apollo-server/issues/4931)
 - `apollo-server-lambda`: Refactor the handler returned by `server.createHandler` so that if it is not passed a callback, it acts as an [async handler](https://docs.aws.amazon.com/lambda/latest/dg/nodejs-handler.html#nodejs-handler-async) instead of a non-async handler. This means you can wrap it in your own async handler without having to create a callback, and makes the code more maintainable. [Issue #1989](https://github.com/apollographql/apollo-server/issues/1989) [PR #5004](https://github.com/apollographql/apollo-server/pull/5004)