WebVTT subtitles not referenced.

[tommie904]

Describe the bug
I am using this package to transcode video and convert it to HLS format for streaming. While it does do that correctly I've ran into an issue where the WebVTT files that it creates aren't referenced or added to the manifests. This has been tested with plenty of video sources and it's the same result.

To Reproduce
Steps to reproduce the behavior:
Just simply get a .mkv file with a subtitle track and use python-ffmpeg-video-streaming to transcode it to HLS format.

Expected behavior
The .vtt files should be referenced in the manifest from my understanding.

Local machine (please complete the following information):

• OS: Windows
• python-ffmpeg-video-streaming 0.1.15