docs.annotatorjs.org should default to 2.x

[BigBlueHat]

@tilgovi per the action you "took" at the community call:
...posted wrong link originally...and have no idea where the old one is... 😕

Could you change the default for the docs to the stable (2.x) docs? And remove the "Beware: rapidly changing documentation!" line? 😄

Thanks! (just reminding)