chore(apps): bump podsteadr-mediamtx to 1.20.0

Released 2026-08-05. Fixes land directly on this app's feature surface:
HLS muxer recomputes AAC PTS in MPEG-TS segments (iOS playback precision,
relevant since the app's config sets hlsVariant: mpegts), fixes a
goroutine leak during HLS part rotation, fixes a Chrome WebRTC "packet
lost" false-positive and non-deterministic WebRTC track ordering (WHIP
ingest), and fixes OBS multitrack RTMP URL parsing. No breaking config
changes; new opt-in features (native forwarding, MoQ draft support)
don't affect this config (moq: no already). Matches the same bump on
the podsteadr repo's docker-compose.yml.

apps/podsteadr-mediamtx/manifest.yml

@@ -1,7 +1,7 @@
 app:
   id: podsteadr-mediamtx
   name: podsteadr MediaMTX
-  version: "1.19.2"
+  version: "1.20.0"
   description: MediaMTX ingest/output backend for podsteadr — RTMP + WebRTC/WHIP ingest, HLS playback, stream recording.
   category: media
 
@@ -12,7 +12,7 @@ app:
   container_name: podsteadr-mediamtx
 
   container:
-    image: docker.io/bluenviron/mediamtx:1.19.2
+    image: docker.io/bluenviron/mediamtx:1.20.0
     pull_policy: if-not-present
     network: podsteadr-net
     network_aliases: [mediamtx]