requires update for ffmpeg 7.0

On Sun, 15 Sep 2024 at 15:18:42 +0200, Timo Röhling wrote:
> pyglet still lacks FFmpeg 7.0 support, but version 2.0.17 no longer requires
> FFmpeg to be present, so I downgraded the Depends to Recommends and this bug
> to severity Important.

I believe missing Recommends are considered RC (Policy §2.2.1 says packages
in main "must not require **or recommend** a package outside of main", and
the older ffmpeg that is compatible with pyglet is no longer in main)
so this probably needs to be a Suggests.

    smcv