Update CONTRIBUTING.md

Syntax highlighting in CONTRIBUTING.md

Co-authored-by: Lukas Spieß <lumaxis@github.com>

CONTRIBUTING.md

@@ -58,7 +58,7 @@ All interactions in the kickerd repository are covered by the [npm Code of Condu
 
 Running the following commands should successfully run the tests:
 
-```
+```shell-script
 # Install node packages
 $ npm install
 # grab the docker file
@@ -130,4 +130,4 @@ You'll need a few things installed in order to update and test the {{project-nam
 
 > We recommend that you have a [node version manager](https://github.com/nvm-sh/nvm) installed if you plan on fixing bugs that might be present in a specific version of node. With a version manager you can easily switch versions of node and test if your changes to the CLI project are working.
 
-* [git](https://git-scm.com/) v2.11+
+* [git](https://git-scm.com/) v2.11+