set flutter_secure_storage to version 8.0.0

Closes #117

Author: rafamizes

CHANGELOG.md

@@ -7,9 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- bump up dependencies — [117](https://github.com/dartoos-dev/json_cache/issues/117).
+
 ## [1.5.1] - 2023-02-05
 
-- bump up dependencies — [109](https://github.com/dartoos-dev/json_cache/issues/112).
+- bump up dependencies — [112](https://github.com/dartoos-dev/json_cache/issues/112).
 
 - stricter linting rules