Changelog: Add entry about C++ wrappers
The `is_zero()` C++ helper for basic data types.
- Added: [[#186](https://github.com/ethereum/evmc/pull/186)]
Reserved the post-Constantinople EVM revision number.
+- Added: [[#187](https://github.com/ethereum/evmc/pull/187)]
+ C++ wrappers for VM and execution result objects.
- Deprecated: [[#184](https://github.com/ethereum/evmc/pull/184)]
The `EVMC_LATEST_REVISION` is deprecated, replaced with `EVMC_MAX_REVISION`.
