An access problem in eslint-module-utils/resolve.js

Hi!

recently ran into an access issue when working with eslint-plugin-import and found this problem:

the file is in the dependency [eslint-module-utils](https://www.npmjs.com/package/eslint-module-utils) which seem to not have it's own repo but is linked to this project

The file is **resolve.js**

here to check if a directory exists the code tries to access a list of files in its parent dir and then find parsedPath.base in received list. This makes an issue when script executor doesn't have access to the directory above

```
const parsedPath = path.parse(filepath);
const dir = parsedPath.dir;

let result = fileExistsCache.get(filepath, cacheSettings);
if (result != null) return result;

// base case
if (dir === '' || parsedPath.root === filepath) {
result = true;
} else {
const filenames = fs.readdirSync(dir);
if (filenames.indexOf(parsedPath.base) === -1) {
result = false;
} else {
result = fileExistsWithCaseSync(dir, cacheSettings, strict);
}
}
```

The same functionality can be implemented this way:

```
if (dir === '' || parsedPath.root === filepath) {
result = true;
} else {
if (!fs.existsSync(path.join(dir, parsedPath.base))) {
result = false;
} else {
result = fileExistsWithCaseSync(dir, cacheSettings, strict);
}
}
```

Start with eslint-module-utils/resolve.js, especially the file-existence check shown in the issue. Reproduce the access failure when the executor cannot read the parent directory, then verify the revised existence check preserves the existing case-sensitive behavior and resolves the reported access problem.

Written by the indexing model from the issue text.