setFontSizeForAllStyles gets ignored

[dkk]

This code returns text with a size of around 15:

    let markdown = SwiftyMarkdown(string: myString)
    markdown.setFontSizeForAllStyles(with: 5.0)
    markdown.setFontColorForAllStyles(with: UIColor.red)
    
    return markdown.attributedString()

on iOS 13.4.1 (iPhone 11 Pro)