react/jsx-no-literals rule shows warning with template strings

Hello,

i'm using eslint@4.10.0 and eslint-plugin-react@7.4.0. The linter shows a warning if a join a string with "template strings", but not if I join it with the + operator:

```
<div className={'test' + name} />
// No warning
```

```
<div className={`test ${name}`} />
// Strings not allowed in JSX files (react/jsx-no-literals)
```

Is this a known issue?

Best regards