Fix typo

Author: ahuarte47

CHANGELOG.md

@@ -8,7 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 - The default Collection objects index can be overridden by the `STAC_COLLECTIONS_INDEX` environment variable.
-- The defualt Item objects index prefix can be overridden by the `STAC_ITEMS_INDEX_PREFIX` environment variable.
+- The default Item objects index prefix can be overridden by the `STAC_ITEMS_INDEX_PREFIX` environment variable.
 
 ## [v0.2.0]