Release KGO OSS v1.2.1

[pmalek]

NOTE: copy pasted from https://github.com/Kong/gateway-operator/issues/8. There's no release template yet in this repo.

Steps

This release pipeline is under continuous improvement. If you encounter any problems, please refer to the troubleshooting section of this document. If the troubleshooting section does not contain the answer to the problem you encountered, please create an issue to improve either the pipeline (if the problem is a bug) or this document (if the problem is caused by human error).

• [x] Check the existing [releases][releases] and determine the next version number.
• [x] Check the default versions of images (see below).
• [x] Check the CHANGELOG.md and update it with the new version number. Make sure it is up to date.
• [x] Ensure that all generators have run properly (e.g. make generate) so that updates to things like CRDs are handled for the release, double check that all manifests from config/samples/ still work as intended.
• [x] Ensure GitHub PAT is still valid (see GitHub PAT below).
• [x] From [GitHub release action][release-action], start a new workflow run with the release input set to the release tag (e.g. v0.1.0).
• [x] Wait for the workflow to complete.
• [x] The CI should create a PR in the [Gateway Operator][kgo-prs] repo that syncs the release branch to the main branch. Merge it.
• [x] After the PR is merged, a new release should be created automatically. Check the [releases][releases] page. The release has to be marked manually as latest if this is the case.

[pmalek]

Release pipeline: https://github.com/Kong/gateway-operator/actions/runs/8346629970