revert and still use PAT (microsoft#157955)

still use PAT

build/azure-pipelines/distro-build.yml

@@ -7,16 +7,26 @@ trigger:
 pr: none
 
 steps:
-  - checkout: self
-    persistCredentials: true
-
   - task: NodeTool@0
     inputs:
       versionSpec: "16.x"
 
+  - task: AzureKeyVault@1
+    displayName: "Azure Key Vault: Get Secrets"
+    inputs:
+      azureSubscription: "vscode-builds-subscription"
+      KeyVaultName: vscode
+      SecretsFilter: "github-distro-mixin-password"
+
   - script: |
       set -e
 
+      cat << EOF > ~/.netrc
+      machine github.com
+      login vscode
+      password $(github-distro-mixin-password)
+      EOF
+
       git config user.email "vscode@microsoft.com"
       git config user.name "VSCode"