Fix "Failed to download metadata ..." error by switching to Rocky Linux.

CentOS is no longer active. Have to choose b/w CentOS Stream or Rocky Linux.

Author: sfgeorge

Dockerfile

@@ -1,13 +1,13 @@
-FROM centos:latest
+FROM rockylinux:latest
 
 EXPOSE 9200
 EXPOSE 5601
 
 ENV ES_VERSION 7.2.0
 ENV KIBANA_VERSION 7.2.0
 
-RUN yum -y install epel-release && yum clean all
-RUN yum -y install unzip zip curl git java-1.8.0-openjdk python2 python2-pip && yum clean all
+RUN dnf -y install epel-release && dnf clean all
+RUN dnf -y install unzip zip curl git java-1.8.0-openjdk python2 python2-pip && dnf clean all
 
 RUN pip2 install --upgrade pip
 RUN pip2 install beautifulsoup4 python-dateutil html5lib lxml tornado retrying pyelasticsearch joblib click chardet