Update istanbul to version 0.4.1 🚀

[greenkeeperio-bot]

Hello :wave:

:rocket::rocket::rocket:

istanbul just published its new version 0.4.1, 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 istanbul – 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 18 commits .

• 42f1bb1 v0.4.1
• f36d197 Add sudo:false to use container infrastructure
• 44b2926 Fix jshint error on node v10
• b8f2e8d Merge pull request #491 from ariya/fix-browser-test
• b10069e Merge pull request #456 from pegurnee/master
• e9f4f88 Merge pull request #467 from RoCat/master
• 6eb3e82 Merge pull request #477 from iphands/master
• 9f44a38 Merge pull request #482 from kpdecker/octal-string
• d8831d0 Merge pull request #490 from ariya/update-esprima
• 97459a8 Workaround the problem of creating escodegen browser bundle (#489)
• 8e95602 Update to latest Esprima 2.7.
• b7b66c5 Prevent babel strict mode error due to strings
• 3387dab sorter click event on the th so that the event is easier to trigger
• d1a602d Merge pull request #441 from adamjmcgrath/es6-modules
• 8883845 fix assetsDir path

There are 18 commits in total. See the full diff.

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