rtp-hdrext-colorspace: Fix color range encoding
The color space RTP header extension encodes color range as specified in https://www.webmproject.org/docs/container/#Range. In other words:
0: Unspecified,
1: Broadcast Range,
2: Full range,
3: Defined by matrix coefficients and transfer characteristic.
This does not match the values of GstVideoColorRange
, so it is not
correct to just write the colorimetry.range
value to the header
extension.