Update mongoose to version 4.9.1 🚀

[greenkeeperio-bot]

Hello lovely humans,

mongoose just published its new version 4.9.1.

State	Update 🚀
Dependency	mongoose
New version	4.9.1
Type	dependency

This version is not covered by your current version range.

Without accepting this pull request your project will work just like it did before. There might be a bunch of new features, fixes and perf improvements that the maintainers worked on for you though.

I recommend you look into these changes and try to get onto the latest version of mongoose.
Given that you have a decent test suite, a passing build is a strong indicator that you can take advantage of these changes by merging the proposed change into your project. Otherwise this branch is a great starting point for you to work on the update.

Do you have any ideas how I could improve these pull requests? Did I report anything you think isn’t right?
Are you unsure about how things are supposed to work?

There is a collection of frequently asked questions and while I’m just a bot, there is a group of people who are happy to teach me new things. Let them know.

Good luck with your project ✨

You rock!

🌴

---

The new version differs by 1172 commits .

• 4f864cf chore: release 4.9.1
• 74cdbdd Merge pull request #5080 from zoellner/master
• 249653b fix(populate): avoid duplicate ids in dynref queries
• dae6192 test: fix flakey test
• 79bf54a fix: upgrade driver -> 2.2.25
• fa2caf5 fix(model): get promise each time save() is called rather than once
• 7d6c259 test: add coverage for #5070
• 2a0df9a fix(connection): make connect return value consistent
• 1a5fffb fix(timestamps): handle nested timestamp paths
• 4efe0dc test(timestamps): repro #5051
• dd3182f docs(validation): add some more detail re: isAsync
• 91866a8 Merge pull request #5072 from sjorssnoeren/gh-5068
• 80b325c fix(query): handle $type for arrays
• 0a88085 fix(update): dont double-call setters on arrays
• 9105d85 test(update): repro #5041

There are 250 commits in total. See the full diff.

---

✨ Try the all new Greenkeeper GitHub Integration ✨
With Integrations first-class bot support landed on GitHub and we’ve rewritten Greenkeeper to take full advantage of it. Simpler setup, fewer pull-requests, faster than ever. Screencast Try it today. Free for private repositories during beta.