webhooks/jira: Ignore issuelink_created events.
webhooks/jira: Ignore issuelink_created events.

Notifications for this event aren't very useful to begin with,
plus exceptions from this event are cluttering up our webhook
error logs.

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