message: [doc] developer-notes.md: point out that UniValue deviates from upstream
diff: @@ -714,7 +714,7 @@ Current subtrees include:
  - Upstream at https://github.com/bitcoin-core/ctaes ; actively maintained by Core contributors.
  - src/univalue
  - - Upstream at https://github.com/jgarzik/univalue ; report important PRs to Core to avoid delay.
  + - Upstream at https://github.com/bitcoin-core/univalue ; actively maintained by Core contributors, deviates from upstream https://github.com/jgarzik/univalue
  Upgrading LevelDB
  ---------------------
  