Update acorn to version 4.0.3 🚀

[greenkeeperio-bot]

Hello lovely humans,

acorn just published its new version 4.0.3.

State	Update 🚀
Dependency	acorn
New version	4.0.3
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 acorn.
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 195 commits .

• bb54adc Mark version 4.0.3
• f83ee7a Allow function declarations in if branches.
• 2b637e1 Revert "Make function-keyword-in-statement-only-position fall through to function expr"
• dede487 Make reserved words in import specifiers a recoverable error.
• dd2a075 Correctly parse properties called 'async' in ES2017 mode.
• 377d9b6 Fall back to previous version's reserved words
• 9e80462 Mark release 4.0.2
• 5ab3d01 forbid yield/await expressions in default parameters
• f7bb90f Revert "forbid yield/await expressions in default parameters"
• b14cb8b Don't ignore period or E characters after octal numbers
• d437659 Update docs to mention ES8/2017
• 6377798 Ensure proper formatting in changelog
• cb95800 Mark release 4.0.1
• 5ab4935 Fix duplicate export checking
• 44f0925 Mark release 4.0.0

There are 195 commits in total. See the full diff.

---

This pull request was created by greenkeeper.io.

_{Tired of seeing this sponsor message? ⚡ greenkeeper upgrade}