update-authors-json: Improve error handling for duplicate commits.
update-authors-json: Improve error handling for duplicate commits.

It's possible that a user with duplicate commits might not be in the
top 100 users for a given repo.

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