Update CHANGELOG.md

Author: tyt2y3

CHANGELOG.md

@@ -50,6 +50,7 @@ assert_eq!(
 * `#[enum_def]` now impl additional `IdenStatic` and `AsRef<str>` https://github.com/SeaQL/sea-query/pull/769
 * Derive `Eq`, `Ord`, `Hash` for `Alias` https://github.com/SeaQL/sea-query/pull/818
 * Replace `Educe` with manual implementations https://github.com/SeaQL/sea-query/pull/817
+* Added `cast_as_quoted` https://github.com/SeaQL/sea-query/pull/789
 
 ### `sea-query-attr`