merging PR #486: Create and update labels improved, close #476
merging PR #486: Create and update labels improved, close #476

https://github.com/chaosbot/Chaos/pull/486: Create and update labels improved, close #476

Description:
Improve label creation

- Attempt to create label
- If label exists update it regardless of changes
- Updating name causes new label creation for compatibility purpose

Use `create_label` all time if this is possible.

NB : [I have tested this PR on my local instance this time !](https://github.com/Swizz/Chaos/labels)

:ok_woman: PR passed with a vote of 11 for and 0 against, a weighted total of 10.5 and a threshold of 6.6, and a current meritocracy review.

Vote record:
@Ayyko: 1
@PlasmaPower: 1
@Smittyvb: 1
@Swizz: 1
@andrewda: 1
@hongaar: 1
@md678685: 1
@phil-r: 1
@qgustavor: 1
@rhengles: 1
@rudehn: 1
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