Update warning to version 3.0.0 🚀

[greenkeeperio-bot]

Hello :wave:

:rocket::rocket::rocket:

warning just published its new version 3.0.0, which is not covered by your current version range.

If this pull request passes your tests you can publish your software with the latest version of warning – otherwise use this branch to work on adaptions and fixes.

Happy fixing and merging :palm_tree:

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The new version differs by 7 commits .

• 6ef2da6 Release 3.0.0
• 7741e46 Merge pull request #9 from leipert/patch-1
• 6bd7ad5 Correct license in package.json
• a262234 Update README.md
• 82e50bf Update README.md
• 5aa9136 Update README.md
• 87782d2 Update README.md

See the full diff.

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[joernroeder]

manually updated to warning ^4.0.0