Update CHANGELOG.md

Author: ascjones

CHANGELOG.md

@@ -21,7 +21,7 @@ crate. All existing sub-crates are reexported and should be used via the new `in
   - Remove the commonly used `use ink_lang as ink` idiom.
   - Replace all usages of individual crates with reexports, e.g. `ink_env` ➜ `ink::env`.
 
-##### Storage Rework
+#### Storage Rework
 [#1331](https://github.com/paritytech/ink/pull/1331) [changes the way](https://github.com/paritytech/ink/issues/1134) 
 `ink!` works with contract storage. Storage keys are generated at compile-time, and user facing traits have been 
 replaced with new abstractions.