Close issue on merge

[prarit]

cmd/mr_create.go: Add --close-issue option

Add an option that allows a user to specify issues that can be closed when
the merge request is merged.  The --close-issue option can be used
multiple times to indicate multiple issues.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>

close #844

[codecov]

Codecov Report

Patch coverage: 56.52% and project coverage change: +0.31 🎉

Comparison is base (cce34e2) 55.25% compared to head (971b5b7) 55.57%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #871      +/-   ##
==========================================
+ Coverage   55.25%   55.57%   +0.31%     
==========================================
  Files          82       82              
  Lines        5961     5988      +27     
==========================================
+ Hits         3294     3328      +34     
+ Misses       2380     2371       -9     
- Partials      287      289       +2     

Impacted Files	Coverage Δ
cmd/mr_show.go	65.80% <0.00%> (-1.52%)	⬇️
cmd/mr_create.go	70.04% <59.09%> (-2.00%)	⬇️

... and 3 files with indirect coverage changes

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[bmeneg]

@prarit, the code rearrangement seems odd. Only func init() is left as the final function, the command creation has been the first bit after lib imports and global var declaration, doesn't it?

[zampierilucas]

@bmeneg I agree, on newly created function we use Run: func(... , so it might be nice to also add it here, since you moving it

[zampierilucas]

What happens if Closes is in the first line? Does it still work?
This is the Gitlab regex just for reference /^\/(?<cmd>close|reopen|...)(?:( |$))(?<arg>[^\/\n]*)(?:\n|$)/
which if you take all the fuzz, it matches that it is at the start of the line without any break line check.

[zampierilucas]

non-blocking-suggestion: This is true for premium/ultimate, as multiple assignees are not allowed on free plan, so I think we should note that on this description, something like:

Suggested change

	mrCreateCmd.Flags().StringSliceP("assignee", "a", []string{}, "set assignee by username; can be specified multiple times for multiple assignees")
	mrCreateCmd.Flags().StringSliceP("assignee", "a", []string{}, "set assignee by username; can be specified multiple times for multiple assignees (multiple assigness is premium gitlab feature)")