Update the "Update Ruby" part for the 8.10 -> 8.11 as well

Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/update/8.10-to-8.11.md

@@ -22,7 +22,9 @@ sudo -u git -H bundle exec rake gitlab:backup:create RAILS_ENV=production
 ### 3. Update Ruby
-If you are you running Ruby 2.1.x, you do not _need_ to upgrade Ruby yet, but you should note that support for 2.1.x is deprecated and we will require 2.3.x in 8.13. It's strongly recommended that you upgrade as soon as possible.
+We will continue supporting Ruby < 2.3 for the time being but we recommend you
+upgrade to Ruby 2.3 if you're running a source installation, as this is the same
+version that ships with our Omnibus package.
 You can check which version you are running with `ruby -v`.