Update release doc with more information (nginx#3506)

docs: Update release doc with more information

Author: salonichf5

docs/developer/release-process.md

@@ -54,7 +54,15 @@ To create a new release, follow these steps:
       the [GitHub releases](https://github.com/nginx/nginx-gateway-fabric/releases) after the release branch is
       created. If included, use the Release Notes specified in a PR.
       - If the supported Gateway API minor version has changed since the last release, add a note to the release notes explaining if the previous version is no longer supported.
-6. Ensure you are on the latest version of the release branch and are up-to-date on all commits, then create and push the release tag in the format `vX.Y.Z`. As a result, the CI/CD pipeline will:
+      - Merge the release PR once it has received all necessary approvals.
+6. Ensure you are on the latest version of the release branch and are up-to-date on all commits, then create and push the release tag in the format `vX.Y.Z`.
+
+   ```shell
+   git tag vX.Y.Z
+   git push upstream vX.Y.Z
+   ```
+
+   As a result, the CI/CD pipeline will:
    - Build NGF, NGINX and NGINX Plus container images with the release tag `X.Y.Z` and push them to the registries.
    - Package and publish the Helm chart to the registry.
    - Create a GitHub release with an autogenerated changelog and attached release artifacts.