renovate/lib/modules/versioning/azure-rest-api/readme.md

The Azure REST APIs use a YYYY-MM-DD version with an optional -preview suffix: https://github.com/microsoft/api-guidelines/blob/vNext/azure/Guidelines.md#api-versioning

Internally at Microsoft they are using other additional suffixes: https://github.com/Azure/bicep/blob/a1d217e3bb3d049fc5c6c21b466c3a29585a6c69/src/Bicep.Core/Analyzers/Linter/ApiVersions/ApiVersionHelper.cs#L15