RTC: Support av1 for Chrome M90 enabled it. 4.0.91

[winlinvip]

Run SRS 4.0.91+ in macOS docker, other OS is here:

docker run --rm -p 1935:1935 -p 1985:1985 -p 8080:8080 \
    --env CANDIDATE=$(ifconfig en0 inet| grep 'inet '|awk '{print $2}') -p 8000:8000/udp \
    registry.cn-hangzhou.aliyuncs.com/ossrs/srs:v4.0.91

Then, use query ?codec=av1 to publish and play with AV1:

• Publish stream: webrtc://localhost/live/livestream?codec=av1
• Play stream: webrtc://localhost/live/livestream?codec=av1

Of course, please upgrade your Chrome to M90+:

The video codec is Video: AV1X, 90000HZ, pt: 35