Update uglify-js to the latest version 🚀

[greenkeeper]

Version 2.8.1 of uglify-js just got published.

Dependency	uglify-js
Current Version	2.8.0
Type	devDependency

The version 2.8.1 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 uglify-js.
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.

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Commits

The new version differs by 3 commits .

• 320984c v2.8.1
• 4365a51 temporarily disables reduce_vars (#1517)
• 858e6c7 warn & drop #__PURE__ iff IIFE is dropped (#1511)

See the full diff.

Not sure how things should work exactly?

There is a collection of frequently asked questions and of course you may always ask my humans.

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Your Greenkeeper Bot 🌴

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}