Grammar tweak in LICENSE-LEVELS.md
Grammar tweak in LICENSE-LEVELS.md

codecombat/codecombat,codecombat/codecombat,javatlacati/codecombat,codecombat/codecombat,javatlacati/codecombat,jeremiahyan/codecombat,jeremiahyan/codecombat,javatlacati/codecombat,jeremiahyan/codecombat,codecombat/codecombat,javatlacati/codecombat,javatlacati/codecombat,jeremiahyan/codecombat,codecombat/codecombat