Support dismissed_review IssueEvent

[gmlewis]

GitHub Developer API announcement:
https://developer.github.com/changes/2018-01-05-dismiss-event-breaking-change/

This announcement actually confuses me a bit...
From the announcement, the dismissed_review IssueEvent is changing, but I don't see any history of it, so I don't know when it was introduced. Nevertheless, we would like to support it, so it needs to be added to the IssueEvent struct in github/issues_events.go.

I think it would suffice to leave its type as a string field, similar to other states returned by this package (as opposed to strictly enumerating the values), unless there are objections.

This would be a great first issue for a new contributor to this repo or new Go developer to work on.
All help is greatly appreciated. Thank you!

[vaibhavsingh97]

@gmlewis I want to solve this issue, just learnt go 😍

[gmlewis]

Excellent! Welcome to the project and to Go in general, @vaibhavsingh97! 😄

I've sent you an invite to collaborate on this repo so once you accept, I can assign this (or any) issue to you.

Check out our CONTRIBUTING.md docs to help you get up and running quickly.

[vaibhavsingh97]

hi @gmlewis can you please assign the issue to me. I will send PR soon 😅

[gmlewis]

Update from GitHub Developer API announcement:
https://developer.github.com/changes/2018-01-17-issue-event-breaking-change/

[simonfl3tcher]

@vaibhavsingh97 are you still planning to take on this issue? If you are tied up right now, I will be happy to help out.

[simonfl3tcher]

FYI - I did not unassign this issue (I don't have access) 🤔. I also don't have access to assign an assignee so can't add you back, sorry @vaibhavsingh97.

cc @gmlewis

I will raise this with the relevant team to see how we can get this bug resolved.

[gmlewis]

Hehe... that's odd. I'm not sure how that unassign happened. Ah, actually I have a theory...

I think around late January we flipped a switch that required all contributors to have two-factor enabled in their account, and it booted out all contributors who didn't. Since GitHub just visited this issue due to your comment, it automatically unassigned.

At least, that's my theory and I'm sticking with it until I hear a better explanation. 😄

Meanwhile, I no longer have permission to send invites from this repo and @vaibhavsingh97 and @mrsimonfletcher don't show up in the list of contributors, so we'll just have to agree on an assignee in the discussion section.

So I'm thinking it is totally safe for you to take this over, @mrsimonfletcher. Thank you!

[waseem18]

I see that there has been no update to #983 since August. @mrsimonfletcher Do you plan to work on this or can I take up the task of addressing the reviews on the PR?