update OTA script in tm-mainline-prod to the latest version.

The last change in tm-mainline-prod was last year (aosp/2040556), did a copy of current version in udc-dev.

Test: local ota
Bug: 279622634
Change-Id: I6563122f21d7213bfa7200e28cdfa69bd95aa3e2
Merged-In: Iaa317a3a4b8addbca8ea987aee9953c78fa1a679
diff --git a/Android.bp b/Android.bp
index cace5b6..cdb492f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1170,3 +1170,11 @@
         "update_metadata-protos",
     ],
 }
+
+python_library_host {
+    name: "update_metadata-protos-python",
+    srcs: ["update_metadata.proto"],
+    proto: {
+        canonical_path_from_root: false,
+    },
+}