chore(README): Clean up badges
chore(README): Clean up badges

Removed the documentation coverage badge since it's not always rendering and there isn't a movement to close down on this. We've also gone a bit different direction since we've been doing flow so deeply.
jdfreder/nteract,captainsafia/nteract,jdetle/nteract,rgbkrk/nteract,temogen/nteract,temogen/nteract,jdfreder/nteract,jdfreder/nteract,nteract/composition,rgbkrk/nteract,0u812/nteract,rgbkrk/nteract,jdetle/nteract,nteract/nteract,rgbkrk/nteract,0u812/nteract,nteract/nteract,nteract/composition,captainsafia/nteract,nteract/nteract,0u812/nteract,captainsafia/nteract,temogen/nteract,captainsafia/nteract,0u812/nteract,jdetle/nteract,jdfreder/nteract,jdetle/nteract,nteract/nteract,rgbkrk/nteract,nteract/nteract,nteract/composition