Use Azure federated auth (#5599)

eng/pipelines/templates/steps/vcpkg.yml

@@ -4,11 +4,12 @@ steps:
       Write-Host "##vso[task.setvariable variable=X_VCPKG_ASSET_SOURCES_SECRET;issecret=true;]clear;x-azurl,https://cppvcpkgcache.blob.core.windows.net/public-vcpkg-asset-container/,,read"
     displayName: Set Vcpkg Variables
 
-  - task: PowerShell@2
-    inputs:
-      pwsh: true
-      targetType: filePath
-      filePath: eng/scripts/Set-VcpkgWriteModeCache.ps1
-      arguments: -StorageAccountKey '$(cpp-vcpkg-cache-storage-key)'
+  - task: AzurePowerShell@5
     displayName: Set Vcpkg Write-mode Cache
     condition: and(succeeded(), eq(variables['System.TeamProject'], 'internal'))
+    inputs:
+      azureSubscription: 'cpp Resource Group'
+      ScriptType: FilePath
+      ScriptPath: eng/scripts/Set-VcpkgWriteModeCache.ps1
+      azurePowerShellVersion: LatestVersion
+      pwsh: true

eng/scripts/Set-VcpkgWriteModeCache.ps1

@@ -1,6 +1,6 @@
 param(
     [string] $StorageAccountName = 'cppvcpkgcache',
-    [string] $StorageAccountKey
+    [string] $ResourceGroupName = 'cpp'
 )
 
 
@@ -27,9 +27,14 @@ $env:PSModulePath = $modulePaths -join $moduleSeperator
 
 Install-ModuleIfNotInstalled "Az.Storage" "4.3.0" | Import-Module
 
+$storageAccountKeys = Get-AzStorageAccountKey `
+    -ResourceGroupName $ResourceGroupName `
+    -Name $StorageAccountName
+
 $ctx = New-AzStorageContext `
-    -StorageAccountName $StorageAccountName `
-    -StorageAccountKey $StorageAccountKey
+    -StorageAccountKey $storageAccountKeys[0].Value`
+    -StorageAccountName $StorageAccountName
+
 $token = New-AzStorageAccountSASToken `
     -Service Blob `
     -ResourceType Object `