Release MSBuild 17.2 - Githubissues

[x] When VS main snaps to 17.3, create vs17.2 branch
[x] When VS main snaps, set change 17.2 loc branch from main to vs17.2 and file a loc exception.
[x] Create darc channel for VS 17.3 if it doesn't already exist \ darc add-channel --name "VS 17.3"
[x] Associate the next release branch with the next release channel \ darc add-default-channel --channel "VS 17.3" --branch vs17.3 --repo https://github.com/dotnet/msbuild
[x] Remove the main to old release channel default channel \ darc delete-default-channel --repo https://github.com/dotnet/msbuild --branch main --channel "VS 17.2"
[x] Associate the main branch with the next release channel \ darc add-default-channel --channel "VS 17.3" --branch main --repo https://github.com/dotnet/msbuild
[x] Check subscriptions for the current channel VS 17.2 and update as necessary (for instance, SDK's main branch should usually be updated \ darc get-subscriptions --exact --source-repo https://github.com/dotnet/msbuild --channel "VS 17.2"
[x] Ensure that the current release channel is associated with the correct release branch\ darc get-default-channels --source-repo https://github.com/dotnet/msbuild --branch vs17.2
[x] Fast-forward merge the correct commit to the vs17.1 branch \ git push upstream 797fd829a374a880f63fd4eea4ea6990404c48f4:refs/heads/vs17.1
[x] Prepare final branding PR for vs17.2 but ⚠️ DO NOT CHECK IN YET ⚠️ #
[x] Promote unshipped public API to shipped in main #7510
1. Get-ChildItem -r src/PublicAPI.*.txt | Clear-Content
2. Open MSBuild.sln in Visual Studio, let it settle
3. Find a green squiggle for the analyzer and fix all in solution
4. Get-ChildItem -r PublicAPI.Unshipped.txt | % { Move-Item -Force -Path $_ (Join-Path $_.Directory.FullName "PublicAPI.Shipped.txt") && New-Item $_ }
[x] Create 17.3 branding PR, including public API change #7501, #7510
[x] Merge 17.3 branding PR
[x] Prepare QB-mode bug for final branding insertion in internal VS repo
[x] Update internal "create VS PR for insertion" release to point to the new VS release branch by default
[x] Merge final branding to vs17.2 branch
[x] Get QB approval
[x] Merge to VS
[x] ASAP after release, push packages to nuget.org (not currently automated, contact dnceng)
[x] Update main subscriptions to the new channel (this can be done after release) \ darc get-subscriptions --exact --target-repo https://github.com/dotnet/msbuild --target-branch main
[x] Create the 17.2 release (https://github.com/dotnet/msbuild/releases/tag/v17.2.1)

dotnet / msbuild

Release MSBuild 17.2 #7459