Update webpack to version 2.5.1 🚀

[greenkeeperio-bot]

🚨🔥⚠️ Action required: Switch to the new Greenkeeper now! 🚨🔥⚠️
This version of Greenkeper will be shutdown on May 31st.
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.

---

Hello lovely humans,

webpack just published its new version 2.5.1.

State	Update 🚀
Dependency	webpack
New version	2.5.1
Type	devDependency

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 webpack.
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!

🌴

---

GitHub Release

Bugfixes:

• Fix crash when error happens while watching
• Fix hoisting of exports

---

The new version differs by 2459 commits .

• ad2f68f 2.5.1
• 4fd545b Merge pull request #4828 from satazor/patch-1
• b0c45da Fix _done function not dealing with compilation being undefined
• 7bc08e1 Merge pull request #4816 from webpack/bugfix/hoist-immutable-export
• a952bb9 change some magic numbers to hoist exports
• bf3652b 2.5.0
• cd1cd29 Merge pull request #4815 from webpack/bugfix/extract-async-initial
• b45588b CommonsChunkPlugin in async mode doesn't select initial chunks
• 8bab88c Merge pull request #4814 from webpack/test/move-entry
• a244879 add testcase for moving entry modules into the commons chunk
• 85dc98f Merge pull request #4813 from JLHwung/perf/date-now
• 6afc397 perf: use Date.now() instead of new Date().getTime()
• 94d0641 perf: use Date.now() instead of +new Date()
• c91ba49 Merge pull request #4791 from deificx/master
• 94ba75f Merge pull request #4794 from ndresx/disable-manifest-json-pretty-print

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