Update Dockerfile

Dockerfile

@@ -9,7 +9,7 @@ $latest = $(curl --silent "https://api.github.com/repos/get-iplayer/get_iplayer/
 echo Current version: $current, Latest version: $latest\n\
 if [[ "$current" -ne "$latest" ]]\n\
 then\n\
-  $tarball = $(curl --silent "https://api.github.com/repos/$1/releases/latest" | grep -Po '"tarball_url": "\K.*?(?=")')\n\
+  $tarball = $(curl --silent "https://api.github.com/repos/get-iplayer/get_iplayer/releases/latest" | grep -Po '"tarball_url": "\K.*?(?=")')\n\
   wget -q $tarball -O /root/latest.tar.gz &&\
   tar -xzf /root/latest.tar.gz -C /root/ &&\
   echo $current > /root/current\n\