Update Dockerfile

Dockerfile

@@ -6,13 +6,15 @@ WORKDIR /mopidy-iris
 
 RUN \
   echo "* Installing Runtime Packages" \
+    && echo "@edge https://nl.alpinelinux.org/alpine/edge/main" >> /etc/apk/repositories \
+    && echo "@commuedge https://nl.alpinelinux.org/alpine/edge/community" >> /etc/apk/repositories \
     && apk add --no-cache \
-      libvpx \
-      gst-plugins-good \
-      gst-plugins-ugly \
-      py2-gst \
-      su-exec \
-      tini \
+      libvpx@edge \
+      gst-plugins-good@commuedge \
+      gst-plugins-ugl@commuedge \
+      py2-gst@commuedge \
+      su-exec@edge \
+      tini@commuedge \
     && pip install -U \
       pyopenssl \
       youtube-dl \