Update dokku-vm dokku version to 0.38.5

[dokku-bot]

No description provided.

[alex-frankel]

Thanks for the auto-bump, @dokku-bot maintainers (@josegonzalez I think?).

Heads-up that our CI requirements changed in April–May 2026. PRs that modify template files (main.bicep/azuredeploy.json) are now required to include a testResult block in metadata.json proving the template was actually deployed successfully. See the contribution guide, specifically the metadata.json schema with the new validationType and testResult fields. The testResult requires a real correlationId and deploymentName from an ARM deployment that we then verify against ADX logs.

We've been merging the prior dokku-bot bumps under a grace period because MAC (AzQuickStarts-MAC) does an actual end-to-end deployment and that gave us deployment-success signal in lieu of the stamp. But the team is moving toward requiring testResult uniformly, including for bot-generated PRs, so the ruleset can move from evaluate to active enforcement.

Could the dokku-bot workflow be updated to:

1. Deploy the bumped template to a throwaway Azure resource group
2. Capture correlationId + deploymentName
3. Stamp metadata.json with the testResult block before opening the PR?

Happy to discuss what that workflow could look like or point at examples — most recently @msmbaldwin's KV PRs (#14759-#14762) follow the pattern.

For this PR specifically: if we don't see an updated commit with a testResult stamp within ~24 hours, we'll merge 0.38.5 as-is to keep dokku users current (MAC is green, so the deployment-success signal is there) — but treat this as the formal heads-up that future bumps should include testResult from the start.

[josegonzalez]

That seems like a reasonable ask, and probably something I can work towards over the next few weeks (feel free to ignore/close PRs while that is in progress). I don't see why we couldn't have that be auto-validated in CI and posted as part of the PR comment.

That said, I don't actually have an Azure subscription and I am wondering if there is some sort of free tier/OSS account I can sign up for that I can perform this work against? Totally fine if not, I can figure out an alternative if so.