fix typo in contribution guidelines

Author: bmuenzenmeyer

.github/CONTRIBUTING.md

@@ -8,7 +8,7 @@ No pull request is too small. Check out any [up for grabs issues](https://github
 2. _ALWAYS_ submit pull requests against the [dev branch](https://github.com/pattern-lab/patternlab-node/tree/dev). If this does not occur, I will first, try to redirect you gently, second, port over your contribution manually if time allows, and/or third, close your pull request. If you have a major feature to stabilize over time, talk to @bmuenzenmeyer about making a dedicated `feature-branch`
 3. If you can, add some unit tests using the existing patterns in the `./test` directory
 
-##Coding style
+## Coding style
 Two files combine within the project to define and maintain our coding style.
 
 * The `.editorconfig` controls spaces / tabs within supported editors. Check out their [site](http://editorconfig.org/).