fix: Remove mentions of Elasticsearch port 9300 (not used anymore).

README.md

@@ -11,7 +11,7 @@ You need to install:
 
 - a recent enough JDK8
 
-The application expects to connect on an ElasticSearch instance running on `http://127.0.0.1:9300`.
+The application expects to connect on an ElasticSearch instance running on `http://127.0.0.1:9200`.
 To have such an instance, simply run:
 
     docker-compose up

docker-compose.yml

@@ -9,7 +9,6 @@ services:
       - "ES_JAVA_OPTS=-Xms2g -Xmx2g -XX:ParallelGCThreads=2"
     ports:
       - 9200:9200
-      - 9300:9300
     ulimits:
       memlock:
         soft: -1