Update VERSION to 9.1.0-pre
Update VERSION to 9.1.0-pre

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