Update .nvmrc to current stable (v9.0.0)
Update .nvmrc to current stable (v9.0.0)

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