Did not upgrade .babelrc file

From what I can gather from the README, this tool should upgrade my `.babelrc` file too, right?

I was running babel 6.x, it updated my package.json with dozens of `"@babel/...": "7.0.0-beta.39"` lines but didn't touch my `.babelrc` file.

Did it fail because I'm using json5 syntax perhaps? Here's my .babelrc file:

```json5
{
// babel uses json5 to parse this file; comments *are* allowed (https://github.com/kadirahq/react-storybook/issues/95#issuecomment-230488360)

"presets": ['@babel/preset-react'],
"plugins": [
// 'add-module-exports',
'syntax-flow',
'syntax-trailing-function-commas',

'check-es2015-constants',

'transform-flow-strip-types',
'transform-es3-member-expression-literals', // http://stackoverflow.com/a/33513000/65387
'transform-es3-property-literals',
'transform-es5-property-mutators',
// ['transform-es2015-modules-commonjs', {loose: true}], // https://babeljs.slack.com/archives/discussion/p1455667909000424 // Webpack 2 should have modules disabled
'transform-class-constructor-call',
'transform-class-properties',
'transform-decorators',
'transform-export-extensions',
'transform-object-rest-spread',
'transform-exponentiation-operator',
'transform-es2015-arrow-functions',
'transform-es2015-block-scoped-functions',
'transform-es2015-block-scoping',
['transform-es2015-classes', {loose: true}], // https://gist.github.com/zertosh/4f818163e4d68d58c0fa, https://github.com/babel/babelify/issues/133
// 'transform-proto-to-assign',
'transform-es2015-computed-properties',
'transform-es2015-destructuring',
'transform-es2015-for-of',
'transform-es2015-function-name',
'transform-es2015-literals',
'transform-es2015-object-super',
'transform-es2015-parameters',
'transform-es2015-shorthand-properties',
'transform-es2015-spread',
'transform-es2015-sticky-regex',
'transform-es2015-template-literals',
'transform-es2015-typeof-symbol',
'transform-es2015-unicode-regex',
['transform-runtime', {"polyfill": true, "regenerator": false}],

// http://stackoverflow.com/a/28709165/65387
// 'syntax-async-functions',
// ['fast-async',{
// compiler: {
// promises: true,
// generators: false
// }
// }],
// 'transform-async-to-generator',
// 'transform-regenerator',

// ['transform-async-to-module-method', {
// module: 'bluebird',
// method: 'coroutine'
// }],
//
// // 'transform-async-to-generator',
// ['transform-regenerator', { // http://babeljs.io/docs/plugins/transform-regenerator/
// asyncGenerators: false, // true by default
// generators: true, // true by default
// async: false // true by default
// }],
],
"env": {
"production": {
"plugins": [
"transform-react-remove-prop-types",
"transform-react-inline-elements",
"transform-react-constant-elements"
]
}
},
"compact": false
}
```

Start with the README's description of upgrades and trace the code that updates package.json to see whether .babelrc is handled. Reproduce the report with the provided JSON5 configuration and check the existing issue comments for expected behavior. Done means a Babel 6 .babelrc configuration is correctly upgraded alongside package.json, with coverage for comments and JSON5 syntax.

Written by the indexing model from the issue text.