[Issue] Publish nightly extension builds

[richardpark-msft]

Two work streams here - the immediate work, and work we'll need as we run long-term:

First-pass

• Publishing releases should go to the Azure Storage blob account
• Re-use the existing build pipelines for extensions, just iterate and loop
• For setting the extension version, we'll use the Build type (ie, manual, scheduled, etc..) to determine if we're going to generate a nightly extension version, rather than just using version.txt.
• New-ReleaseNotesFile.ps1 might need changes to make sure it doesn't error out for a CHANGELOG that's not updated (ie, has a release date).
• (publish-extension.yaml): Publish_Release, should have a condition to check what the conditions are - if it runs it'll require an approval.
  • add in a daily folder
  • delete the _manifest folder.
• Nightly builds should use the trigger for scheduling, and not a schedule block in the YAML itself.
  • Only trigger nightly builds on source changes. (@JeffreyCA also loves this!)

Follow up

• Extension sources should probably show up more prominently once we're set on the design. This was just a first pass, using the existing extension sources, but @vhvb1989 was thinking we could make this a first class concept, which would reduce manual configuration.
• Use git-push-changes.yaml for pushing the extensions changes for the extensions manifest.
• 'dev' builds might actually be publishing to the storage account already, but if not, we want to publish to a storage path that contains the version.
• Use the GitHub App for our token
• Move the check for the build.reason into the inline powershell script instead of template {else}
• Update-NightlyExtensionRegistry.ps1 ergonomics - set default values and doc the parameters
• Cleanup for nightly builds - how long do we keep releases and how do we cleanup old ones?
• Version numbers for nightly builds - we went with a <current-version.txt>-nightly.buildnumber but we might want something else.

[richardpark-msft]

CC: @danieljurek

[JeffreyCA]

Do we want to only trigger nightly builds on source changes? It should work fine for Go extensions, which are our first target.

Yes that seems reasonable to me, especially considering we have quite a few azure.ai extensions, and not all are updated on a regular basis

[richardpark-msft]

Do we want to only trigger nightly builds on source changes? It should work fine for Go extensions, which are our first target.

Yes that seems reasonable to me, especially considering we have quite a few azure.ai extensions, and not all are updated on a regular basis

And done, the extensions pipelines are all set to only schedule when there are changes.