For issues, get field `state_reason` to distinguish issues closed as `not_planned`

[andreasabel]

For issues, get field state_reason to distinguish issues closed as not_planned.
This amounts to a new enum type IssueStateReason and a new field in Issue which should be parsed here:

github/src/GitHub/Data/Issues.hs

Lines 186 to 205 in f63f92c

	instance FromJSON Issue where
	parseJSON = withObject "Issue" $ \o -> Issue
	<$> o .:? "closed_at"
	<*> o .: "updated_at"
	<*> o .: "events_url"
	<*> o .: "html_url"
	<*> o .:? "closed_by"
	<*> o .: "labels"
	<*> o .: "number"
	<*> o .: "assignees"
	<*> o .: "user"
	<*> o .: "title"
	<*> o .:? "pull_request"
	<*> o .: "url"
	<*> o .: "created_at"
	<*> o .: "body"
	<*> o .: "state"
	<*> o .: "id"
	<*> o .: "comments"
	<*> o .:? "milestone"

According to https://docs.github.com/en/rest/issues/issues?apiVersion=2022-11-28#get-an-issue the possible values are

• completed
• not_planned
• reopened
• null