gitattributes: Mark yarn.lock as "binary", i.e. suppress diffs.
gitattributes: Mark yarn.lock as "binary", i.e. suppress diffs.

This makes many diffs that touch our JS dependencies in package.json
much, much more readable by suppressing multi-thousand-line changes.
With that kind of change routine, it's clear this isn't a file people
are closely reviewing the text diffs in anyway.

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