Merge branch 'docs/updating-distro-link' into 'master'

Docs: Adding link to installation page with recommended distro versions listed

Closes gitlab-com/support/docs#60

See merge request gitlab-org/gitlab!29279

doc/install/requirements.md

@@ -11,10 +11,10 @@ as the hardware requirements that are needed to install and use GitLab.
 
 ### Supported Linux distributions
 
-- Ubuntu
-- Debian
-- CentOS
-- openSUSE
+- Ubuntu (16.04/18.04)
+- Debian (8/9/10)
+- CentOS (6/7/8)
+- openSUSE (Leap 15.1/Enterprise Server 12.2)
 - Red Hat Enterprise Linux (please use the CentOS packages and instructions)
 - Scientific Linux (please use the CentOS packages and instructions)
 - Oracle Linux (please use the CentOS packages and instructions)