CHANGELOG: move changelog entry for GH-1150 to unreleased

[david-yu]

Changes proposed in this PR:

• Move changelog for merged PR from 0.42.0 to UNRELEASED: Add annotation for explicitly specifying which service you want registered #1150

How I've tested this PR:

How I expect reviewers to test this PR:

Checklist:

• Tests added
• CHANGELOG entry added

  HashiCorp engineers only, community PRs should not add a changelog entry.
  Entries should use present tense (e.g. Add support for...)

[andrewstucki]

@david-yu whoops, it looks like I accidentally added the changelog entry to the wrong section -- it's here right now:

consul-k8s/CHANGELOG.md

Line 49 in 4c640fc

* Add a `"consul.hashicorp.com/kubernetes-service"` annotation for pods to specify which Kubernetes service they want to use for registration when multiple services target the same pod. [[GH-1150](https://github.com/hashicorp/consul-k8s/pull/1150)]

Do you think you could drop it in this PR too? 😅 😊

[t-eckert]

Looks ok once you remove the existing entry on line 49.