Add @vinilage to CODEOWNERS of changelog/ dir (#464)

# Summary

Automatically add @vinilage as required reviewer for `changelog/` files
modification.

## Proof of Work

no-op

## Checklist

- [ ] Have you linked a jira ticket and/or is the ticket in the title?
- [x] Have you checked whether your jira ticket required DOCSP changes?
- [x] Have you added changelog file?
    - use `skip-changelog` label if not needed
- refer to [Changelog files and Release
Notes](https://github.com/mongodb/mongodb-kubernetes/blob/master/CONTRIBUTING.md#changelog-files-and-release-notes)
section in CONTRIBUTING.md for more details

Author: MaciejKaras

.github/CODEOWNERS

@@ -1 +1,3 @@
 * @mongodb/kubernetes-hosted
+
+/changelog/ @mongodb/kubernetes-hosted @vinilage