mailmap: Add Git .mailmap for zulipchat.com → zulip.com.
mailmap: Add Git .mailmap for zulipchat.com → zulip.com.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulip.com>

andersk/zulip,punchagan/zulip,shubhamdhama/zulip,zulip/zulip,brainwane/zulip,rht/zulip,synicalsyntax/zulip,brainwane/zulip,rht/zulip,eeshangarg/zulip,andersk/zulip,showell/zulip,hackerkid/zulip,zulip/zulip,showell/zulip,shubhamdhama/zulip,hackerkid/zulip,hackerkid/zulip,punchagan/zulip,showell/zulip,zulip/zulip,eeshangarg/zulip,showell/zulip,timabbott/zulip,zulip/zulip,kou/zulip,shubhamdhama/zulip,timabbott/zulip,kou/zulip,showell/zulip,rht/zulip,andersk/zulip,synicalsyntax/zulip,shubhamdhama/zulip,synicalsyntax/zulip,eeshangarg/zulip,punchagan/zulip,showell/zulip,brainwane/zulip,andersk/zulip,brainwane/zulip,shubhamdhama/zulip,zulip/zulip,eeshangarg/zulip,punchagan/zulip,eeshangarg/zulip,brainwane/zulip,zulip/zulip,kou/zulip,punchagan/zulip,hackerkid/zulip,shubhamdhama/zulip,showell/zulip,rht/zulip,kou/zulip,rht/zulip,synicalsyntax/zulip,andersk/zulip,kou/zulip,timabbott/zulip,shubhamdhama/zulip,synicalsyntax/zulip,eeshangarg/zulip,hackerkid/zulip,punchagan/zulip,eeshangarg/zulip,hackerkid/zulip,timabbott/zulip,brainwane/zulip,andersk/zulip,brainwane/zulip,rht/zulip,synicalsyntax/zulip,kou/zulip,synicalsyntax/zulip,timabbott/zulip,rht/zulip,andersk/zulip,timabbott/zulip,timabbott/zulip,zulip/zulip,punchagan/zulip,hackerkid/zulip,kou/zulip