[Doppins] Upgrade dependency sinon to ^3.2.1

[doppins-bot]

Hi!

A new version was just released of sinon, so Doppins
has upgraded your project's dependency ranges.

Make sure that it doesn't break anything, and happy merging!

---

Upgraded sinon from ^2.0.0 to ^3.0.0

[coveralls]

Coverage remained the same at 99.254% when pulling 4e984c5 on doppins/sinon-from-3.0.0-below-4.0.0 into ddd9c54 on master.

[doppins-bot]

An additional new version was just released of sinon, so we've added an
extra commit upgrading your range to ^3.1.0.

Hope that's alright!
— Doppins

[coveralls]

Coverage remained the same at 99.254% when pulling 3037010 on doppins/sinon-from-3.0.0-below-4.0.0 into ddd9c54 on master.

[doppins-bot]

An additional new version was just released of sinon, so we've added an
extra commit upgrading your range to ^3.2.1.

Hope that's alright!
— Doppins

[coveralls]

Coverage remained the same at 99.254% when pulling ccf2b63 on doppins/sinon-from-3.0.0-below-4.0.0 into ddd9c54 on master.