Fix cloudron installation on netcup

https://forum.cloudron.io/topic/10097/cloudron-install-error-dpkg-error/
https://twitter.com/netcup/status/1735265955364720757

scripts/init-ubuntu.sh

@@ -25,6 +25,12 @@ apt-get -o Dpkg::Options::="--force-confdef" update -y
 apt-get -o Dpkg::Options::="--force-confdef" upgrade -y
 apt-mark unhold grub* >/dev/null
 
+# workaround netcup setting immutable bit. can be removed in 8.0
+if lsattr -l /etc/resolv.conf 2>/dev/null | grep -q Immutable; then
+    echo "==> Fixing up /etc/resolv.conf"
+    chattr -i /etc/resolv.conf
+fi
+
 echo "==> Installing required packages"
 
 debconf-set-selections <<< 'mysql-server mysql-server/root_password password password'