message: Create 1.0.0-beta3 CHANGELOG section
diff: @@ -6,6 +6,8 @@ and this project adheres to
  ## [Unreleased]
  +## [1.0.0-beta3]
  +
  ### Added
  - cosmwasm-std: New const methods `Uint64::to_be_bytes`/`::to_le_bytes`.
  @@ -1202,7 +1204,9 @@ Some main points:
  All future Changelog entries will reference this base
  -[unreleased]: https://github.com/CosmWasm/cosmwasm/compare/v1.0.0-beta...HEAD
  +[unreleased]: https://github.com/CosmWasm/cosmwasm/compare/v1.0.0-beta3...HEAD
  +[1.0.0-beta3]:
  + https://github.com/CosmWasm/cosmwasm/compare/v1.0.0-beta...v1.0.0-beta3
  [1.0.0-beta]: https://github.com/CosmWasm/cosmwasm/compare/v0.16.2...v1.0.0-beta
  [0.16.2]: https://github.com/CosmWasm/cosmwasm/compare/v0.16.1...v0.16.2
  [0.16.1]: https://github.com/CosmWasm/cosmwasm/compare/v0.16.0...v0.16.1
  