Replaced MariaDB library to MySQL 8

proxy-mysql/centos/Dockerfile

@@ -31,11 +31,12 @@ RUN set -eux && \
     mkdir -p /usr/lib/zabbix/externalscripts && \
     mkdir -p /usr/share/doc/zabbix-proxy-mysql && \
     dnf --quiet makecache && \
-    dnf -y install http://repo.zabbix.com/non-supported/rhel/8/x86_64/fping-3.16-1.el8.x86_64.rpm --setopt=tsflags=nodocs && \
+    dnf -y install epel-release && \
     dnf -y install --setopt=tsflags=nodocs --setopt=install_weak_deps=False --best \
             libcurl-minimal \
             libevent \
             libssh \
+            fping \
             libxml2 \
             mariadb \
             net-snmp-libs \