[Keyvault] Regenerate swagger using Autorest Typescript v6

[joheredi]

This issue tracks the work to re-generate the sawgger using the latest version of @autorest/typescript

In order to use the new generator 2 changes need to be done in swagger/readme.md files

v3: true
use-extension:
  "@autorest/typescript": "6.0.0-dev.20200618.1"

Note
The latest @autorest/typescript version can be found here

[ramya-rao-a]

@sadasant,

Lets have 3 separate PRs for the 3 Keyvault packages using the same swagger files that were used to generate what is in the master branch. There should be no net functional change for the end user with these changes. The only change would be in the generated client and how the convenience layer talks to the generated client.

[sadasant]

Now that I have a better picture of what's required to update this, I need to go back to the drawing board. There are some updates that are potentially public API changes. I'm asking the feature crew.

[sadasant]

Likely no need for API changes. But more clarity on what properties we’re sending.

[sadasant]

I had to close my latest PR. The latest Autorest & Autorest Typescript forces us to use api-version 7.1. It doesn't allow us to specify api-version 7.0, which is a regression. We'll come back to this issue during the next release cycle.

[sadasant]

Also, for the record:
This made me realize we weren't sending a property in createKey: #11245 (comment)

Which led to this new issue: #11263

[sarangan12]

The keyvault-keys package migration has been completed in this PR - #13092

[sarangan12]

The keyvault-secrets package migration has been completed in this PR - #12821

[sarangan12]

The keyvault-certificates package migration has been completed in this PR - #12820