Issue-4769 - Unable to update case of label

Labels are saved in the database with the case they were originally created with.
Before this change if a user created a label with the same text but different case
the label would use the original case and no new label would be created in the
database. With this change, labels are now case-sensitive.

Steps to test:

1. Before this change, create a new issue with a new label "FIxMe"
2. Edit the issue and change the label to "FixMe"
3. Note that the label reverted to "FIxMe"
4. Apply this change
5. Edit the issue again and change the label to "FixMe"
Note that the new case was preserved. If you also look in the database in the "tags" table you will see that both labels are present - "FIxMe" and "FixMe".
Allow searching by namespace name, include public projects

GITLAB-1457 (GITLAB-836)

Change-Id: If8e2474bc6908accca51f395f58937687f101b58
Read configuration variable file if it is present
Add 6.0-to-6.2 update guide
Escape strings

Signed-off-by: Nigel Kukard <nkukard@lbsd.net>
Include a note if there are security fixes.
Fix Markdown help page: escape file link syntax example to leave it unprocessed
Accept our license agreement.
Add numbers.
Fix numbering by indenting.
Best to escape strings not split them

Signed-off-by: Nigel Kukard <nkukard@lbsd.net>
Merge pull request #5475 from nkukard/esc-strings

Escape strings
Correctly escape search query
Require gitlab-shell v1.7.3
Merge pull request #5435 from karlhungus/feature_search_namespace_name_and_public

Allow searching by namespace name, include public projects
Mention security improvements in CHAGENLOG for 6.3
Mention GitLab CI 4.0 in CHANGELOG

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Show only first line of commit message on dashboard

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Fix sidekiq start text in documentation and gitlab:check
Merge pull request #5487 from perryfaro/fix-sidekiq-documentation

Change documentation about sidekiq