ESlint: Missing file extension for jquery when configured as webpack externals using the webpack resolver

`import $ from 'jquery';` triggers `import/extensions` and when the js extension is added, `import/no-unresolved`.

my .eslintrc is:

```
{
"env": {
"browser": true,
"es6": true
},
"extends": [
"airbnb-base",
"prettier"
],
"parser": "babel-eslint",
"plugins": [
"prettier"
],
"root": true,
"rules": {
"indent": ["error", 4, { "SwitchCase": 1 }],
"no-plusplus": ["error", { "allowForLoopAfterthoughts": true }],
"no-underscore-dangle": 0,
"prettier/prettier": "error"
},
"settings": {
"import/ignore": ["\\.(scss|less|css)$"],
"import/resolver": {
"webpack": {
"config": "./webpack.config.js"
}
}
}
}
```

webpack.config.js has

```
externals: {
jquery: 'jQuery'
},
```

Note that the build works as intended with the latest version of eslint, webpack and all other modules..

Start with the reported .eslintrc settings and webpack.config.js externals entry for jquery, then reproduce the conflicting import/extensions and import/no-unresolved results. Trace the webpack resolver's handling of externals and verify that the jquery import is resolved consistently without either error.

Written by the indexing model from the issue text.