fix: Explicitly make entrypoint of 'setup' service executable

The existing executable permission might not be preserved when users
download docker-elk as a Zip file.

Fixes #676

setup/Dockerfile

@@ -4,8 +4,14 @@ ARG ELASTIC_VERSION
 FROM docker.elastic.co/elasticsearch/elasticsearch:${ELASTIC_VERSION}
 
 USER root
-RUN mkdir /state && chown elasticsearch /state
-USER elasticsearch:root
 
 COPY . /
+
+RUN set -eux; \
+	mkdir /state; \
+	chown elasticsearch /state; \
+	chmod +x /entrypoint.sh
+
+USER elasticsearch:root
+
 ENTRYPOINT ["/entrypoint.sh"]