Avocado-related: block PRs on violations of non-uniform version of SDK package in README.md

From:
- https://github.com/Azure/azure-rest-api-specs-pr/pull/17601#issuecomment-2036116397

> Please note that when you define a package in the readme.md file, that ALL swaggers MUST share the same api-version.
>
> So, 'package-2024-04-01-preview' MUST have all its input files be 2024-04-01-preview.
> Right now, you show this:
> input-file:
>
> Microsoft.PortalServices/copilotSettings/preview/2024-04-01-preview/copilotSettings.json
> Microsoft.PortalServices/dashboards/preview/2024-01-01-preview/dashboards.json
> Microsoft.PortalServices/extensions/preview/2024-03-01-preview/extensions.json
> By definition, an Azure service is a set of operation endpoints that version uniformly. This is a requirement so that customers know what version of a service they are using, what SDK version targets that service version, which service version to use for documentation, which service version introduces any future breaking change, which version they are using if they need to contact customer support, and so on.
>
> In the near future, our repo tooling will catch these versioning violations and forbid merging of the PR.
> For now, please fix this manually.

Related work:
- https://github.com/Azure/azure-rest-api-specs/pull/28464

Related doc:
- https://aka.ms/azsdk/uniform-versioning