add `gst-plugins-good` in PKGBUILD for arch linux

I had this line  `GStreamer element autoaudiosink not found. Please install it` and couldn't start playing a song, after installing `gst-plugins-good` it worked.

I now have `WebKit wasn't able to find a WebVTT encoder. Subtitles handling will be degraded unless gst-plugins-bad is installed.` but installing it only get rid of the message without having any noticeable improvement so I didn't put it in the PKGBUILD since the plugin have a lot of dependencies.