update dev dependencies, add new demo gif, optimize npm package

Author: bastidest

CHANGELOG.MD

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.3.4] - 2020-07-18
+### Security
+- Update dev dependencies
+
 ## [0.3.3] - 2020-03-19
 ### Added
 - Add description of additional props (#5)

README.md

@@ -1,7 +1,7 @@
 #   Vue Step Progress Bar
 
 ##  Demo
-![demo gif](https://user-images.githubusercontent.com/1242917/36874916-15c773c2-1dae-11e8-8780-595903b79018.gif)
+![demo gif](./demo.gif)
 
 ##  Installation