Fix readme (#61)

* fix: error in the README file

* Update CHANGELOG.md

Author: rafamizes

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+Error in the README file.
+
 ## [1.1.0] - 2022-01-28
 
 ### Added

README.md

@@ -213,7 +213,7 @@ is an implementation on top of the
 
   // later on…
 
-  final mappedInfo = await jsonCache.value('secret')!;
+  final mappedInfo = (await jsonCache.value('secret'))!;
   final originalInfo = mappedInfo.keys.first; // 'an secret info'
 ```