feat: update changelog to reflect protobufs being updated
* `TransactionId.[Set|Get]Scheduled()` - Supports scheduled transaction IDs.
* `TransactionIdWithValidStart()`
+### Fixed
+
+ * Updated protobufs [#120](https://github.com/hashgraph/hedera-sdk-go/issues/120)
+
### Deprecate
* `NewTransactionId()` - Use `TransactionIdWithValidStart()` instead.
