[ci]: add official build for mellanox

Signed-off-by: Guohan Lu <lguohan@gmail.com>

.azure-pipelines/official-build.yml

@@ -28,6 +28,14 @@ stages:
       raw_image: true
       sync_rpc_image: true
 
+  - template: build-template.yml
+    parameters:
+      platform: mellanox
+      platform_short: mlnx
+      cache_mode: wcache
+      dbg_image: true
+      sync_rpc_image: true
+
   - template: build-template.yml
     parameters:
       platform: vs