EXT-X-VERSION can be optional in HlsMasterContent

[mchenx]

when try to parse an HlsMasterContent, it throws exception saying "Playlist missing required EXT-X-VERSION tag."

I think a hls master play list file should be valid without EXT-X-VERSION, it's optional

[jonathan-haubrich]

https://datatracker.ietf.org/doc/html/rfc8216#section-4-3-1-2

EXT-X-VERSION is optional if the file contains only tags that are supported in version 1, otherwise it’s required.

Would probably be pretty simple to verify as there aren’t that many tags.