Update links to development principles
gitlab-com/www-gitlab-com!103539 (merged) moves this handbook page - this updates links in the development docs.
Part of gitlab-com/chief-of-staff-cto#18.
gitlab-com/www-gitlab-com!103539 (merged) moves this handbook page - this updates links in the development docs.
Part of gitlab-com/chief-of-staff-cto#18.