Update babel-plugin-istanbul to the latest version 🚀

[greenkeeper]

Version 4.0.0 of babel-plugin-istanbul just got published.

Dependency	babel-plugin-istanbul
Current Version	3.1.2
Type	devDependency

The version 4.0.0 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 babel-plugin-istanbul.
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 6 commits .

• ac8abab chore(release): 4.0.0
• e902924 fix: load configuration from process.env.NYC_CONFIG if present (#93)
• f77db2a feat: we can now use the language feature Object.assign (#92)
• 80afed9 docs(readme): add Greenkeeper badge 🌴 (#89)
• 594c03a feat: drop Node 0.10 and 0.12 support, upgrade dependencies to reflect this (#88)
• f0b8d7e chore(package): update test-exclude to version 4.0.0 (#86)

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 🌴