Fix changelog

Author: marcqualie

CHANGELOG.md

@@ -7,12 +7,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 
-## [0.3.1] - 2020-07-08
+## [Unreleased]
 
 ### Added
 
 - CLI: `diffcrypt generate-key` command to generate a new key for a cipher
 
+
+
+## [0.3.1] - 2020-07-08
+
 ### Fixed
 
 - Thor deprecation error no longer shows on CLI failure