Add text documenting that v5 of the API will be GraphQL
Add text documenting that v5 of the API will be GraphQL

[ci skip]

dreampet/gitlab,axilleas/gitlabhq,dplarson/gitlabhq,jirutka/gitlabhq,dplarson/gitlabhq,dreampet/gitlab,t-zuehlsdorff/gitlabhq,iiet/iiet-git,jirutka/gitlabhq,t-zuehlsdorff/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,dreampet/gitlab,mmkassem/gitlabhq,stoplightio/gitlabhq,iiet/iiet-git,dplarson/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,stoplightio/gitlabhq,iiet/iiet-git,dreampet/gitlab,dplarson/gitlabhq,t-zuehlsdorff/gitlabhq,jirutka/gitlabhq,jirutka/gitlabhq,t-zuehlsdorff/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq