docker-compose: elasticsearch: reduce JVM heap

see https://github.com/inventaire/inventaire-deploy/commit/c2a9365

docker-compose.yml

@@ -30,6 +30,7 @@ services:
       - 'transport.host=127.0.0.1'
       # See https://www.elastic.co/guide/en/elasticsearch/reference/7.14/docker.html
       - 'discovery.type=single-node'
+      - 'ES_JAVA_OPTS=-Xms1g -Xmx1g'
     ports :
       - '127.0.0.1:9200:9200'
     volumes: