Update CHANGELOG for 8.10.7, 8.9.8, and 8.8.9
Update CHANGELOG for 8.10.7, 8.9.8, and 8.8.9

[ci skip]

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