Move `update_merge_request` ability to Developer
Move `update_merge_request` ability to Developer

Closes #13663

screenpages/gitlabhq,darkrasid/gitlabhq,SVArago/gitlabhq,daiyu/gitlab-zh,openwide-java/gitlabhq,darkrasid/gitlabhq,iiet/iiet-git,dreampet/gitlab,LUMC/gitlabhq,stoplightio/gitlabhq,dplarson/gitlabhq,screenpages/gitlabhq,dwrensha/gitlabhq,shinexiao/gitlabhq,icedwater/gitlabhq,mmkassem/gitlabhq,mr-dxdy/gitlabhq,martijnvermaat/gitlabhq,mr-dxdy/gitlabhq,mr-dxdy/gitlabhq,axilleas/gitlabhq,martijnvermaat/gitlabhq,icedwater/gitlabhq,dplarson/gitlabhq,iiet/iiet-git,shinexiao/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,axilleas/gitlabhq,dwrensha/gitlabhq,stoplightio/gitlabhq,larryli/gitlabhq,darkrasid/gitlabhq,icedwater/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,Soullivaneuh/gitlabhq,jirutka/gitlabhq,shinexiao/gitlabhq,t-zuehlsdorff/gitlabhq,allysonbarros/gitlabhq,daiyu/gitlab-zh,martijnvermaat/gitlabhq,allysonbarros/gitlabhq,LUMC/gitlabhq,daiyu/gitlab-zh,mr-dxdy/gitlabhq,larryli/gitlabhq,daiyu/gitlab-zh,axilleas/gitlabhq,htve/GitlabForChinese,screenpages/gitlabhq,iiet/iiet-git,jirutka/gitlabhq,openwide-java/gitlabhq,ttasanen/gitlabhq,jirutka/gitlabhq,stoplightio/gitlabhq,htve/GitlabForChinese,screenpages/gitlabhq,SVArago/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,t-zuehlsdorff/gitlabhq,allysonbarros/gitlabhq,icedwater/gitlabhq,openwide-java/gitlabhq,mmkassem/gitlabhq,allysonbarros/gitlabhq,dreampet/gitlab,larryli/gitlabhq,dreampet/gitlab,mmkassem/gitlabhq,SVArago/gitlabhq,Soullivaneuh/gitlabhq,LUMC/gitlabhq,Soullivaneuh/gitlabhq,dwrensha/gitlabhq,dplarson/gitlabhq,htve/GitlabForChinese,martijnvermaat/gitlabhq,openwide-java/gitlabhq,dplarson/gitlabhq,dwrensha/gitlabhq,Soullivaneuh/gitlabhq,htve/GitlabForChinese,darkrasid/gitlabhq,LUMC/gitlabhq,shinexiao/gitlabhq,ttasanen/gitlabhq,ttasanen/gitlabhq,larryli/gitlabhq,ttasanen/gitlabhq,SVArago/gitlabhq,iiet/iiet-git,t-zuehlsdorff/gitlabhq