title: React-Dropzone, accepted files MIME type error
body: <p>I´m currently building a react drop zone for obvious reason, but am getting those weird errors:</p>
  <pre><code>Skipped &quot;accepted&quot; because it is not a valid MIME type. Check https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types for a list of valid MIME types.
  </code></pre>
  <p>You can define the data type, which will be accepted by the dropzone.
  It looks as follows:</p>
  <pre><code>useDropzone({
      accept: { accepted: ['image/png', 'image/jpeg'] },
      maxFiles: 1,
      multiple: false,
      onDrop: (acceptedFiles) =&gt; {
        setFiles(
          acceptedFiles.map((file) =&gt;
            Object.assign(file, {
              preview: URL.createObjectURL(file)
            })
          )
        );
      }
    });
  </code></pre>
  <p>there you can also see the accept key, from which im getting the error message.
  It has that weird syntax because of TypeScript:</p>
  <pre><code>export interface Accept {
    [key: string]: string[];
  }
  </code></pre>
  <p>That´s the expected type for the accept- key.</p>
  <p>Any ideas on why I´m getting this weird error message?
  (I also deactivated TS in that line and got the same message.</p>
  <p>For some reason the code still works tho... So other files, which aren´t images are accepted...
  Glad for any help- cheers!</p>