Remove workarounds for .NET 5 RTM builds (#14038)

build.psm1

@@ -1773,11 +1773,6 @@ function Start-PSBootstrap {
 
     Write-Log -message "Installing PowerShell build dependencies"
 
-    # Temporary workaround to consume .NET 5 pre-release RTM build. Remove after .NET 5 RTM. Details: https://github.com/PowerShell/PowerShell/issues/13974
-    if ($Version -eq '5.0.100') {
-        $Version = '5.0.100-rtm.20526.5'
-    }
-
     Push-Location $PSScriptRoot/tools
 
     try {

nuget.config

@@ -2,7 +2,6 @@
 <configuration>
   <packageSources>
     <clear />
-    <add key="dotnet5-rtm" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/5.0.100-rtm.20526.5/nuget/v3/index.json" />
     <add key="dotnet5" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet5/nuget/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
     <add key="dotnet-core" value="https://dotnet.myget.org/F/dotnet-core/api/v3/index.json" />

test/hosting/NuGet.Config

@@ -2,7 +2,6 @@
 <configuration>
   <packageSources>
     <clear />
-    <add key="dotnet5-rtm" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/5.0.100-rtm.20526.5/nuget/v3/index.json" />
     <add key="powershell-core" value="https://powershell.myget.org/F/powershell-core/api/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
     <add key="dotnet-core" value="https://dotnet.myget.org/F/dotnet-core/api/v3/index.json" />

tools/releaseBuild/azureDevOps/templates/nuget.yml

@@ -34,13 +34,6 @@ jobs:
     displayName: 'Use .NET Core SDK from global.json'
     inputs:
       version: '$(SDKVersion)'
-    condition: ne(variables['SDKVersion'], '5.0.100')
-
-  - pwsh: |
-      Import-Module "$(Build.SourcesDirectory)/build.psm1" -Force
-      Install-Dotnet -Version '5.0.100-rtm.20526.5'
-    displayName: Install-DotNet
-    condition: eq(variables['SDKVersion'], '5.0.100')
 
   - task: DownloadBuildArtifacts@0
     displayName: 'Download PowerShell build artifacts'