chore(ci): get rid of 0.10

[hiroppy]

Please Read the CONTRIBUTING Guidelines
In particular the portion on Commit Message Formatting

Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior? (You can also link to an open issue here)

https://travis-ci.org/babel/babel-loader/jobs/188429204
Node.js version v0.10.48 does not meet requirement for yarn. Please use Node.js 4 or later.

What is the new behavior?

There is no error probably.

Does this PR introduce a breaking change?

• Yes
• No

If this PR contains a breaking change, please describe the following...

• Impact:
• Migration path for existing applications:
• Github Issue(s) this is regarding:

Other information:

[codecov-io]

Current coverage is 80.92% (diff: 100%)

Merging #354 into master will not change coverage

@@             master       #354   diff @@
==========================================
  Files             6          6          
  Lines           152        152          
  Methods          23         23          
  Messages          0          0          
  Branches         33         33          
==========================================
  Hits            123        123          
  Misses           13         13          
  Partials         16         16          

Powered by Codecov. Last update 3900952...ac4f505

[danez]

When we do this (dropping support for node <4, as 0.12 is also unsupported), we probably should release a new major version? What do you think?

[hiroppy]

@danez Sorry for my late reply. I think we should release a major version to inform everyone and to avoid trouble with npm install