Use latest logstash

Author: whyscream

test_config_syntax.sh

@@ -11,5 +11,5 @@ set -eux
 docker run --rm -it \
   --volume "$(pwd)"/postfix.grok:/etc/logstash/patterns.d/postfix.grok \
   --volume "$(pwd)"/50-filter-postfix.conf:/usr/share/logstash/pipeline/50-filter-postfix.conf \
-  logstash:8.12.0 \
+  logstash:8.14.1 \
   logstash --config.test_and_exit -f /usr/share/logstash/pipeline/50-filter-postfix.conf