Cut 1.21.7+k3s1

[cwayne18]

Summary:
Task covering patch release work.

Dev Complete: 11/10 (Typically ~1 week prior to upstream release date)

List of required releases:
To release as soon as able for QA:

• 1.21.7+k3s1

To release once have approval from QA:

• 1.21.7+k3s1 (Never release on a Friday unless specified otherwise)

Prep work:

• PM: Dev and QA team to be notified of the incoming releases - add event to team calendar
• PM: Dev and QA team to be notified of the date we will mark the latest release as stable - add event to team calendar [ONLY APPLICABLE FOR LATEST MINOR RELEASE]
• QA: Review changes and understand testing efforts
• Release Captain: Prepare release notes in our private release-notes repo (submit PR for changes taking care to carefully check links and the components, once merged, create the release in GitHub and mark as a draft and check the pre-release box, fill in title, set target release branch, leave tag version blank for now until we are ready to release)
• QA: Validate and close out all issues in the release milestone.

Vendor and release work:

• Release Captain: Vendor in the new patch version and release rancher/kubernetes
• Release Captain: Tag and release any necessary RCs for QA to test K3s and KDM on the Rancher side
• Release Captain: Tag and release when have QA approval

Post-Release work:

• Release Captain: Once release is fully complete (CI is all green and all release artifacts exist), edit the release, uncheck "Pre-release", and save.
• Release Captain: Prepare PRs as needed to update KDM in the appropriate dev branches.
• PM: Close the milestone in GitHub.