update repository references and improve script handling

arpspoof/rootfs/etc/cont-init.d/99-run.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bashio
+# shellcheck shell=bash
+set -e
+
+# Avoid unbound variables
+set +u
+
+# Autodefine if not defined
+if [ -n "$INTERFACE_NAME" ]; then
+    # shellcheck disable=SC2155
+    export INTERFACE_NAME="$(ip route get 8.8.8.8 | sed -nr 's/.*dev ([^\ ]+).*/\1/p')"
+    bashio::log.blue "Autodetection : INTERFACE_NAME=$INTERFACE_NAME"
+fi
+
+bashio::log.info "Starting..."
+/usr/bin/python3 /opt/arpspoof/arpspoof.py