fix broken dockerfile

Image is broken because of outdated packages.

Also needs to be mandated to use UTC time, otherwise .ts files are out of sync with the backend.

nginx/Dockerfile

@@ -1,7 +1,11 @@
-FROM tiangolo/nginx-rtmp
+FROM tiangolo/nginx-rtmp:latest-2026-09-07
 
-RUN apt-get update && \
+ENV TZ=UTC
+
+RUN apt-get update -o Acquire::Check-Valid-Until=false && \
     apt-get install -y --no-install-recommends gettext-base && \
+    ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && \
+    echo $TZ > /etc/timezone && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 COPY default.conf.template /etc/nginx/templates/default.conf.template