fix(core): updating instructions on how to generate the changelog for releases (#1587)

Author: lirantal

CONTRIBUTING.md

@@ -51,7 +51,7 @@ Example implementation in file.js
 Fixes #82
 ```
 
-* Types: 
+* Types:
   * feat - Features, Enhancements, and overall Improvements
   * fix - Fixes, Bugs, HotFixs, etc...
   * doc - Changes to the Documentation and doesn't actually touch any code.
@@ -82,4 +82,6 @@ The code for the documentation and the website are located in the meanjs/mean re
 
 For those who will be generating releases:
 * Don't forget to update the changelog!
-  * `conventional-changelog -r 1 | cat - CHANGELOG.md | tee CHANGELOG.md`
+  * Install the changelog cli tool: `npm install conventional-changelog-cli`
+  * Generate the updated changelog `node_modules/.bin/conventional-changelog -r 1 > /tmp/release && cat CHANGELOG.md >> /tmp/release && cat /tmp/release > CHANGELOG.md && rm /tmp/release`
+	* Review, and commit changes