docs(contribution): format terminal commands (#231)

Author: rtpHarry

CONTRIBUTING.md

@@ -2,6 +2,7 @@
 
 Temporary release process until #213 is done:
 
+```
 cd lib
 npm run build
 npm run release
@@ -10,3 +11,4 @@ vim package.json #tick the version number manually
 npm run build
 cd dist
 npm publish
+```