chore: Update default Windows VHDs to Sept 2021 images

[marosset]

Signed-off-by: Mark Rossetti marosset@microsoft.com

Reason for Change:

Issue Fixed:

Credit Where Due:

Does this change contain code from or inspired by another project?

• No
• Yes

If "Yes," did you notify that project's maintainers and provide attribution?

• No
• Yes

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[marosset]

@jsturtevant @jackfrancis
This just includes 9B patches. I have opened a PR to include 9C patches and we can release those as a separate VHD if they pass validation.

[jackfrancis]

Got it, so this update isn't meant to be for a new aks-engine release? (with new k8s versions still in the progress of merging...)

[marosset]

Got it, so this update isn't meant to be for a new aks-engine release? (with new k8s versions still in the progress of merging...)

This has some fixes we've been waiting for for upstream tests.
We can make a new VHD w/ new versions and 9C patches for the next release.

[jackfrancis]

/lgtm