ci: test Node.js 8, 10 and 11

[DanielRuf]

Node.js 9 has reached its EOL and we should check the current LTS 8 and 10 and current stable (11) - to fail early.

[coveralls]

Pull Request Test Coverage Report for Build 55

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 64.744%

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Totals
Change from base Build 54:	0.0%
Covered Lines:	75
Relevant Lines:	101

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💛 - Coveralls

[papandreou]

Looks like the HTTP mocking library also has trouble with node.js 11.2.0. Let's track that here: moll/node-mitm#55

I'm pretty sure that subfont itself works fine with node 11, but it would be really nice to not have to assume that :)

[DanielRuf]

I'm pretty sure that subfont itself works fine with node 11, but it would be really nice to not have to assume that :)

Exactly. Thanks for creating and tracking the issue.

[papandreou]

Got it fixed now and published new versions of the underlying libraries.

[papandreou]

🚀

[papandreou]

@DanielRuf, thanks for taking the initiative :)

[DanielRuf]

Thank you too for creating and maintaining subfont and the great collaboration.