Hosted Pipelines Image Deprecation

This post details the deprecation and upcoming retirement of specific hosted pipeline images: `ubuntu-16.04`, `macOS-10.14`, `vs2017-win2016`, and `windows-latest` (which will soon reference `windows-2019`). It provides YAML snippets for updating pipelines to use newer images like `macOS-10.15`, `macOS-11`, `ubuntu-18.04`, `ubuntu-20.04`, `windows-2019`, and `windows-2022`. It also outlines methods for identifying pipelines using deprecated images, including checking agent queues in Azure DevOps and using a PowerShell script to query job history. Migration advice includes switching to `windows-2019` or upgrading Visual Studio projects.