Update dependencies from https://github.com/dotnet/arcade build 20200528.4 (#7676)

Microsoft.DotNet.Arcade.Sdk
 From Version 5.0.0-beta.20261.9 -> To Version 5.0.0-beta.20278.4

Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>

eng/common/post-build/publish-using-darc.ps1

@@ -0,0 +1,71 @@
+param(
+  [Parameter(Mandatory=$true)][int] $BuildId,
+  [Parameter(Mandatory=$true)][string] $AzdoToken,
+  [Parameter(Mandatory=$true)][string] $MaestroToken,
+  [Parameter(Mandatory=$false)][string] $MaestroApiEndPoint = 'https://maestro-prod.westus2.cloudapp.azure.com',
+  [Parameter(Mandatory=$true)][string] $WaitPublishingFinish,
+  [Parameter(Mandatory=$true)][string] $EnableSourceLinkValidation,
+  [Parameter(Mandatory=$true)][string] $EnableSigningValidation,
+  [Parameter(Mandatory=$true)][string] $EnableNugetValidation,
+  [Parameter(Mandatory=$true)][string] $PublishInstallersAndChecksums,
+  [Parameter(Mandatory=$false)][string] $ArtifactsPublishingAdditionalParameters,
+  [Parameter(Mandatory=$false)][string] $SigningValidationAdditionalParameters
+)
+
+try {
+  . $PSScriptRoot\post-build-utils.ps1
+  . $PSScriptRoot\..\darc-init.ps1
+
+  $optionalParams = [System.Collections.ArrayList]::new()
+
+  if ("" -ne $ArtifactsPublishingAdditionalParameters) {
+    $optionalParams.Add("artifact-publishing-parameters") | Out-Null
+    $optionalParams.Add($ArtifactsPublishingAdditionalParameters) | Out-Null
+  }
+
+  if ("false" -eq $WaitPublishingFinish) {
+    $optionalParams.Add("--no-wait") | Out-Null
+  }
+
+  if ("true" -eq $PublishInstallersAndChecksums) {
+    $optionalParams.Add("--publish-installers-and-checksums") | Out-Null
+  }
+
+  if ("true" -eq $EnableNugetValidation) {
+    $optionalParams.Add("--validate-nuget") | Out-Null
+  }
+
+  if ("true" -eq $EnableSourceLinkValidation) {
+    $optionalParams.Add("--validate-sourcelinkchecksums") | Out-Null
+  }
+
+  if ("true" -eq $EnableSigningValidation) {
+    $optionalParams.Add("--validate-signingchecksums") | Out-Null
+
+    if ("" -ne $SigningValidationAdditionalParameters) {
+      $optionalParams.Add("--signing-validation-parameters") | Out-Null
+      $optionalParams.Add($SigningValidationAdditionalParameters) | Out-Null
+    }
+  }
+
+  & darc add-build-to-channel `
+	--id $buildId `
+	--default-channels `
+	--source-branch master `
+	--azdev-pat $AzdoToken `
+	--bar-uri $MaestroApiEndPoint `
+	--password $MaestroToken `
+	@optionalParams
+
+  if ($LastExitCode -ne 0) {
+    Write-Host "Problems using Darc to promote build ${buildId} to default channels. Stopping execution..."
+    exit 1
+  }
+
+  Write-Host 'done.'
+} 
+catch {
+  Write-Host $_
+  Write-PipelineTelemetryError -Category 'PromoteBuild' -Message "There was an error while trying to publish build '$BuildId' to default channels."
+  ExitWithExitCode 1
+}