* Bump 5.0 SDK and runtimes to 6.0
* Make it very clear that Powershell 7 is required
The new `#Requires` line makes the DoAll script fail fast with a helpful error:
> .\DoAll.ps1 : The script 'DoAll.ps1' cannot be run because it contained a "#requires" statement for Windows PowerShell 7.0. The version of Windows PowerShell that is required by the script does not match the currently running version of Windows PowerShell 5.1.22000.653.
Before this, the user may get some weird error about `Select-String -Raw` not working.
* Fix BuildSdk.proj default build
It doesn't like to be *built*. It only likes to be packed.
* Improve discovery of VS installations
* Install the .NET 5 runtime for ClangSharpPInvokeGenerator
Mike Battista
Andrew Arnott
Rose
Andrew Arnott
Rafael Rivera