Fix exporter command

conf/chaperone.d/elasticsearch-exporter.conf

 exporter.service: {
-    command: "sh -c 'exec /usr/sbin/elasticsearch_exporter -es.indices -es.uri http://127.0.0.1:${PORT} -web.listen-address :${EXPORTER_PORT}'",
+    command: "/bin/sh -c 'exec /usr/sbin/elasticsearch_exporter -es.indices -es.uri http://127.0.0.1:${PORT} -web.listen-address :${EXPORTER_PORT}'",
     restart: true,
 }