Update when to version 3.7.4 🚀

[greenkeeperio-bot]

Hello :wave:

:rocket::rocket::rocket:

when just published its new version 3.7.4, which is not covered by your current version range.

If this pull request passes your tests you can publish your software with the latest version of when – otherwise use this branch to work on adaptions and fixes.

Happy fixing and merging :palm_tree:

---

The new version differs by 23 commits .

• be5316e Bump version
• 2942895 Merge pull request #471 from cujojs/use-npm-poly
• bec863e Use poly from npm
• ccd6970 Merge pull request #465 from stevage/patch-1
• 93d5faa Update api.md
• 38e915b Remove iojs, since its node-gyp fails spectacularly on travis
• 78047c9 Update travis config for container infra
• 9359e84 Merge pull request #463 from anthonyvia/master
• bc3cb70 Unindent helper function.
• 0553dcb Unindent keys.settle function one level.
• 2f6cfc6 Extract helper function from keys.settle function so that it is only created once.
• 0413b69 Merge pull request #464 from emilyrose/patch-2
• f872aa4 Update api.md
• 9aa48c3 Simplify keys.settle implementation.
• e73b1fb Add implementation for keys.settle

There are 23 commits in total. See the full diff.

---

This pull request was created by greenkeeper.io. It keeps your software, up to date, all the time.

_{Tired of seeing this sponsor message? Upgrade to the supporter plan! You'll also get your pull requests faster :zap:}