hello: Fix link to legacy GitHub integration.
hello: Fix link to legacy GitHub integration.

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