CodeGeneration.targets flags github PR links as GithubUrlsWithoutHash

[christothes]

example

D:\a\1\s\eng\CodeGeneration.targets(38,5): error : Following GitHub URLs do not contain commit hash: https://github.com/Azure/azure-rest-api-specs/pull/10262 please use permalinks for code generation inputs (see https://help.github.com/en/github/managing-files-in-a-repository/getting-permanent-links-to-files) [D:\a\1\s\sdk\keyvault\Azure.Security.KeyVault.Administration\src\Azure.Security.KeyVault.Administration.csproj]

[pakrym]

I think this is correct. We want a link pointing to a specific version of the file even if it's part of the RP.