improve regrex for match(sidekiq) robustness

e.g.: the sidekiq in my Debian box is v2.11.1
changed Gitlab to GitLab
Merge pull request #3990 from bbodenmiller/patch-gitlab-cap

changed Gitlab to GitLab in user facing locations
Better remove project message
Version up to 5.2
Replace 5-1-stable with 5-2-stable in installation docs
Fix cancel button link on edit files page
Merge pull request #4018 from dolphin333/fix_cancel_button_link_on_edit_files_page

Fix cancel button link on edit files page
handle broken diffs gracefully
include namespace in project path for system hook
Fix huge MR exceptions. Fixed link to diff for it
Use separate property for project path and project path with namespace inside system hook
Replace all occurs of {{created_at}} at project wall
Make service code more abstract
Add more fields to project service model
Add tinder for future campfire integration
Mention methods that should be implemented inside service
Campfire service added
Fix service tests in spinach
Fixed typo in Readme.md

Fixed 22th -> 22nd