Merge pull request #305 from jpogran/maint-update-changelog

(maint) Update CHANGELOG with missed issues

Author: glennsarti

CHANGELOG.md

@@ -24,6 +24,7 @@ Check [Keep a Changelog](http://keepachangelog.com/) for recommendations on how
 - ([GH-240](https://github.com/lingua-pupuli/puppet-vscode/issues/240)) Add TCP retry functionality
 - ([GH-296](https://github.com/lingua-pupuli/puppet-vscode/issues/296)) Set document file scheme
 - ([GH-289](https://github.com/lingua-pupuli/puppet-vscode/issues/289)) Fix autoindenting for DSL
+- ([GH-301](https://github.com/lingua-pupuli/puppet-vscode/issues/301)) Fail fast if agent not installed
 
 ## 0.10.0 - 2018-03-29