Merge branch '41293-fix-command-injection-vulnerability-on-system_hook_push-queue-through-web-hook-10-2' into 'security-10-2'

[10.2] Don't allow line breaks on HTTP headers

See merge request gitlab/gitlabhq!2287

(cherry picked from commit 1e19734413d46346dd46177d056d9c7165602197)

b7664b12 Don't allow line breaks on HTTP headers