'inaccessible due to 'internal' protection level.'

[JeromeCHA]

https://github.com/mokumoku/SwiftWebViewProgress/blob/e54cc76bcedd43c067d7d0231fb8f582649a8db9/SwiftWebViewProgress/SwiftWebViewProgress/SwiftWebViewProgressView.swift#L14

The progressBarView is not "open", so we cannot customize it.

For example, we cannot change the progressTintColor

progressView.progressBarView.progressTintColor = UIColor.red