Disable automatic crate update in OBS

Use the versions from the Cargo.lock file to have
consistent builds. If a crate needs to be updated
run `cargo update` in Git and commit the changes.

rust/package/_service

@@ -14,7 +14,7 @@
   <service name="cargo_vendor" mode="manual">
     <param name="srcdir">agama/rust</param>
      <param name="compression">zst</param>
-     <param name="update">true</param>
+     <param name="update">false</param>
   </service>
   <service name="cargo_audit" mode="manual">
     <param name="srcdir">agama/rust</param>