Babel configuration in package.json interferes with Webpack

I'm running Webpack with Babel in my project, but not using the ES2015 preset. Webpack gives me this error:

```
ERROR in ./node_modules/jsonml-to-react-element/lib/index.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Couldn't find preset "es2015" relative to directory "/Users/reidar/projects/djupvik.digital/node_modules/jsonml-to-react-element"
```

I believe this error message is because of the Babel configuration in the bundled `package.json`:

```
"babel": {
"presets": [
"es2015"
]
},
```

Start by inspecting the bundled package.json and the Babel configuration referenced in the issue, then reproduce the Webpack build with babel-loader. Verify how the package's preset declaration is applied, and consider the issue complete when consumers no longer receive an unwanted es2015 preset lookup.

Written by the indexing model from the issue text.