fix: arc-theme moves to ppa:fcwu-tw/apps

Author: dorowu-qnap

Dockerfile

@@ -6,9 +6,7 @@ RUN sed -i 's#http://archive.ubuntu.com/#http://tw.archive.ubuntu.com/#' /etc/ap
 # built-in packages
 RUN apt-get update \
     && apt-get install -y --no-install-recommends software-properties-common curl \
-    && sh -c "echo 'deb http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_16.04/ /' >> /etc/apt/sources.list.d/arc-theme.list" \
-    && curl -SL http://download.opensuse.org/repositories/home:Horst3180/xUbuntu_16.04/Release.key | apt-key add - \
-    && add-apt-repository ppa:fcwu-tw/ppa \
+    && add-apt-repository ppa:fcwu-tw/apps \
     && apt-get update \
     && apt-get install -y --no-install-recommends --allow-unauthenticated \
         supervisor \