Upgrade to GStreamer 1.28.0

I've tried a local build of this, and it seems to work. Still doesn't
solve the weird stuttering issues I see on a lot of channels, though.
In fact, I'm not sure how long those issues have been around, or if they
exist beyond the "lowpower" pipeline and the tiny SBC I now run this on.

Author: featherbread

Dockerfile

@@ -6,7 +6,7 @@ ARG GOLANG_BASE=docker.io/library/golang:1.26-alpine3.23
 # The Node.js image doesn't require any particular OS.
 ARG NODEJS_BASE=docker.io/library/node:24-alpine
 # See https://gstreamer.freedesktop.org/news/.
-ARG GSTREAMER_VERSION=1.26.10
+ARG GSTREAMER_VERSION=1.28.0
 
 # Mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git.
 # Since this is formally marked as a "public mirror" in the GitHub web UI, my