Update CHANGELOG for 8.7.7 release
Update CHANGELOG for 8.7.7 release

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