[chore] update release instructions to update the -releases changelog (…

…#11846)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
This change is paired with
open-telemetry/opentelemetry-collector-releases#769

docs/release.md

@@ -106,24 +106,26 @@ The last step of the release process creates artifacts for the new version of th
 
 2. Update the builder version in `OTELCOL_BUILDER_VERSION` to the new release in the `Makefile`. While this might not be strictly necessary for every release, this is a good practice.
 
-3. Create a pull request with the change and ensure the build completes successfully. See [example](https://github.com/open-telemetry/opentelemetry-collector-releases/pull/71).
+3. Run `make chlog-update VERSION="${RELEASE_VERSION}"` with the version of the artifacts.
+
+4. Create a pull request with the change and ensure the build completes successfully. See [example](https://github.com/open-telemetry/opentelemetry-collector-releases/pull/71).
    -  🛑 **Do not move forward until this PR is merged.** 🛑
 
-4. Check out main and ensure it has the "Prepare release" commit in your local
+5. Check out main and ensure it has the "Prepare release" commit in your local
    copy by pulling in the latest from
    `open-telemetry/opentelemetry-collector-releases`. Assuming your upstream
    remote is named `upstream`, you can try running:
    - `git checkout main && git fetch upstream && git rebase upstream/main`
 
-5. Create a tag for the new release version by running:
+6. Create a tag for the new release version by running:
 
    ⚠️ If you set your remote using `https` you need to include `REMOTE=https://github.com/open-telemetry/opentelemetry-collector-contrib.git` in each command. ⚠️
 
    - `make push-tags TAG=v0.85.0`
 
-6. Wait for the new tag build to pass successfully.
+7. Wait for the new tag build to pass successfully.
 
-7. Ensure the "Release Core", "Release Contrib", "Release k8s", and "Builder - Release" actions pass, this will
+8. Ensure the "Release Core", "Release Contrib", "Release k8s", and "Builder - Release" actions pass, this will
 
     1. push new container images to `https://hub.docker.com/repository/docker/otel/opentelemetry-collector`, `https://hub.docker.com/repository/docker/otel/opentelemetry-collector-contrib` and `https://hub.docker.com/repository/docker/otel/opentelemetry-collector-k8s`
 
@@ -133,6 +135,8 @@ The last step of the release process creates artifacts for the new version of th
 
     4. build and push ocb Docker images to `https://hub.docker.com/r/otel/opentelemetry-collector-builder` and the GitHub Container Registry within the releases repository
 
+9. Update the release notes with the CHANGELOG.md updates.
+
 ## Troubleshooting
 
 1. `unknown revision internal/coreinternal/v0.85.0` -- This is typically an indication that there's a dependency on a new module. You can fix it by adding a new `replaces` entry to the `go.mod` for the affected module.