Update CONTRIBUTING.md (#2302)
Update CONTRIBUTING.md (#2302)


mozilla/idea-town-server,chuckharmston/testpilot,lmorchard/testpilot,mathjazz/testpilot,flodolo/testpilot,mozilla/idea-town,mozilla/idea-town-server,mathjazz/testpilot,chuckharmston/testpilot,lmorchard/idea-town,mozilla/idea-town,fzzzy/testpilot,meandavejustice/testpilot,mozilla/idea-town,meandavejustice/testpilot,lmorchard/testpilot,flodolo/testpilot,lmorchard/idea-town-server,mathjazz/testpilot,meandavejustice/testpilot,mozilla/idea-town-server,mozilla/idea-town,lmorchard/idea-town,lmorchard/testpilot,lmorchard/testpilot,flodolo/testpilot,meandavejustice/testpilot,lmorchard/idea-town-server,flodolo/testpilot,mozilla/idea-town-server,fzzzy/testpilot,chuckharmston/testpilot,chuckharmston/testpilot,lmorchard/idea-town,lmorchard/idea-town,lmorchard/idea-town-server,lmorchard/idea-town-server,mathjazz/testpilot,fzzzy/testpilot,fzzzy/testpilot