fix(docker): exit codes above 255 are invalid

entrypoint.sh

@@ -1,5 +1,5 @@
 #!/bin/bash
 
-host=db; port=3306; n=120; i=0; while ! (echo > /dev/tcp/$host/$port) 2> /dev/null; do [[ $i -eq $n ]] && >&2 echo "$host:$port not up after $n seconds, exiting" && exit $port; echo "waiting for $host:$port to come up"; sleep 1; i=$((i+1)); done
+host=db; port=3306; n=120; i=0; while ! (echo > /dev/tcp/$host/$port) 2> /dev/null; do [[ $i -eq $n ]] && >&2 echo "$host:$port not up after $n seconds, exiting" && exit 1; echo "waiting for $host:$port to come up"; sleep 1; i=$((i+1)); done
 
 pdns_server --daemon=no