Get started with Swashbuckle and ASP.NET Core

Swashbuckle update (#18974)

* Update to current version

* cleanup AddSwaggerGen snippets

* moving OpenApiInfo to proper location

* powerapps and flow version note 2.0 example

* annotations update

* annotations edit

* edit pass

* fix note

* update line number

Co-authored-by: Scott Addie <10702007+scottaddie@users.noreply.github.com>