Update CHANGELOG.md for 13.10.1-ee

CHANGELOG.md

changelogs/unreleased/mimemagic_shim.yml

...unreleased/remove-direct-mimemagic-dependency-minimal.yml

changelogs/unreleased/remove-direct-mimemagic-dependency.yml

changelogs/unreleased/remove_hipchat_gem.yml

changelogs/unreleased/security-fix-xss-in-mr-sidebar.yml

...s/unreleased/security-id-leave-pool-for-private-forks.yml

...gs/unreleased/security-kroki-arbitraryfile-read-write.yml

...nreleased/security-projects-branch-collaboration-loop.yml

...elogs/unreleased/security-trigger-system-hook-by-post.yml