prepare changelog for 0.14.0 (#76)

Author: efd6

CHANGELOG.md

@@ -6,7 +6,17 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
-- Added `minify_json` template helper function for minifying static JSON: [#x](https://github.com/elastic/stream/pull/x)
+### Changed
+
+### Fixed
+
+### Removed
+
+## [0.14.0]
+
+### Added
+
+- Added `minify_json` template helper function for minifying static JSON: [#74](https://github.com/elastic/stream/pull/74)
 
 ### Changed