Update CHANGELOG.md for 10.3.5
Update CHANGELOG.md for 10.3.5

[ci skip]
axilleas/gitlabhq,stoplightio/gitlabhq,dreampet/gitlab,jirutka/gitlabhq,dreampet/gitlab,dreampet/gitlab,mmkassem/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,stoplightio/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq,iiet/iiet-git,stoplightio/gitlabhq,jirutka/gitlabhq,axilleas/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,mmkassem/gitlabhq,jirutka/gitlabhq,iiet/iiet-git,dreampet/gitlab,stoplightio/gitlabhq,jirutka/gitlabhq