docs: Document need to enable Universe repository on Ubuntu.
docs: Document need to enable Universe repository on Ubuntu.

brainwane/zulip,brainwane/zulip,hackerkid/zulip,dhcrzf/zulip,eeshangarg/zulip,kou/zulip,eeshangarg/zulip,kou/zulip,synicalsyntax/zulip,hackerkid/zulip,synicalsyntax/zulip,kou/zulip,jackrzhang/zulip,synicalsyntax/zulip,timabbott/zulip,hackerkid/zulip,synicalsyntax/zulip,andersk/zulip,rishig/zulip,shubhamdhama/zulip,dhcrzf/zulip,shubhamdhama/zulip,andersk/zulip,rht/zulip,dhcrzf/zulip,rht/zulip,jackrzhang/zulip,kou/zulip,kou/zulip,jackrzhang/zulip,jackrzhang/zulip,timabbott/zulip,tommyip/zulip,rishig/zulip,punchagan/zulip,andersk/zulip,timabbott/zulip,tommyip/zulip,tommyip/zulip,eeshangarg/zulip,rishig/zulip,rishig/zulip,eeshangarg/zulip,tommyip/zulip,rht/zulip,shubhamdhama/zulip,shubhamdhama/zulip,jackrzhang/zulip,zulip/zulip,hackerkid/zulip,synicalsyntax/zulip,hackerkid/zulip,kou/zulip,rht/zulip,rishig/zulip,punchagan/zulip,rht/zulip,synicalsyntax/zulip,zulip/zulip,punchagan/zulip,punchagan/zulip,tommyip/zulip,showell/zulip,brainwane/zulip,zulip/zulip,tommyip/zulip,jackrzhang/zulip,rishig/zulip,zulip/zulip,andersk/zulip,rishig/zulip,punchagan/zulip,brainwane/zulip,shubhamdhama/zulip,showell/zulip,zulip/zulip,andersk/zulip,timabbott/zulip,shubhamdhama/zulip,kou/zulip,tommyip/zulip,brainwane/zulip,rht/zulip,brainwane/zulip,timabbott/zulip,dhcrzf/zulip,brainwane/zulip,andersk/zulip,dhcrzf/zulip,punchagan/zulip,timabbott/zulip,hackerkid/zulip,showell/zulip,showell/zulip,dhcrzf/zulip,jackrzhang/zulip,zulip/zulip,shubhamdhama/zulip,zulip/zulip,andersk/zulip,rht/zulip,showell/zulip,synicalsyntax/zulip,hackerkid/zulip,eeshangarg/zulip,timabbott/zulip,showell/zulip,eeshangarg/zulip,punchagan/zulip,eeshangarg/zulip,showell/zulip,dhcrzf/zulip