Update supported version page for 5.20 (#2438)
Update supported version page for 5.20 (#2438)

Co-authored-by: Edgar Valdes <9e3230fdeb6c7cab0154356bc0e7294ccbea2831@sensu.io>
sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs