docs: Update supported OS

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

doc/install/requirements.md

@@ -13,11 +13,11 @@ the minimum requirements needed to install and use GitLab.
 
 ### Supported Linux distributions
 
-- Ubuntu (16.04/18.04/20.04)
-- Debian (9/10)
+- Ubuntu (18.04/20.04)
+- Debian (9/10/11)
 - AlmaLinux (8)
 - CentOS (7)
-- openSUSE Leap (15.2)
+- openSUSE Leap (15.3)
 - SUSE Linux Enterprise Server (12 SP2/12 SP5)
 - Red Hat Enterprise Linux (use the AlmaLinux or CentOS instructions)
 - Scientific Linux (use the CentOS instructions)