Update MIGRATING.md with new version number

Co-authored-by: Simon Warta <[email protected]>

Author: uint

Diff for: MIGRATING.md

@@ -4,7 +4,7 @@ This guide explains what is needed to upgrade contracts when migrating over
 major releases of `cosmwasm`. Note that you can also view the
 [complete CHANGELOG](./CHANGELOG.md) to understand the differences.
 
-## 1.0.0 -> ?
+## 1.0.0 -> 1.1.0
 
 - There are changes to how we generate schemas, resulting in less boilerplace
   maintenance for smart contract devs. The changes are backwards-compatible -