Updating ES Dockerfile (#739)

* - updating ES dockerfile, by adding missing packages and switching to python3

* - joined commands to reduce layers on the docker image
- fixed formatting
- added elasticsearch-dsl

Co-authored-by: doublebyte1 <info@doublebyte.net>

docker/examples/elastic/ES/Dockerfile

@@ -41,6 +41,8 @@ USER root
 COPY docker-entrypoint.sh  /docker-entrypoint.sh
 COPY add_data.sh /add_data.sh
 
+RUN yum install -y wget
+
 RUN wget https://raw.githubusercontent.com/vishnubob/wait-for-it/master/wait-for-it.sh -O bin/wait-for-it.sh
 RUN chmod +x bin/wait-for-it.sh
 RUN wget https://raw.githubusercontent.com/geopython/pygeoapi/master/tests/data/ne_110m_populated_places_simple.geojson -O ${DATA_FOLDER}/ne_110m_populated_places_simple.geojson
@@ -50,9 +52,8 @@ RUN echo "xpack.security.enabled: false" >> config/elasticsearch.yml
 RUN echo "http.host: 0.0.0.0" >> config/elasticsearch.yml
 
 RUN yum --enablerepo=extras -y install epel-release \
-	&& yum install -y python-pip \
-	&& yum install -y python-setuptools \
-	&& pip install --upgrade pip && pip install elasticsearch \
+        && yum install -y python3 python3-pip python3-setuptools python-typing \
+        && pip3 install --upgrade pip elasticsearch elasticsearch-dsl \
 	&& yum clean packages
 
 USER elasticsearch