push-to-pull-request: Give a nice error if `jq` missing.
push-to-pull-request: Give a nice error if `jq` missing.

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