message: correct searchguard version
diff: ARG IMAGE_REPO
  FROM ${IMAGE_REPO:-lagoon}/elasticsearch:6
  -RUN bin/elasticsearch-plugin install -b com.floragunn:search-guard-6:6.8.2-25.3 \
  +RUN bin/elasticsearch-plugin install -b com.floragunn:search-guard-6:6.8.2-25.4 \
  && chmod a+x plugins/search-guard-6/tools/install_demo_configuration.sh \
  && plugins/search-guard-6/tools/install_demo_configuration.sh -y \
  && sed -i 's/searchguard.ssl.http.*//' config/elasticsearch.yml \
  