fix ISO8601 datetime format for dump

docker-tools/mongodump/run.sh

@@ -2,5 +2,5 @@
 
 mongodump --host mongo --out /tmp/ --db eventman
 cd /tmp
-tar cfz /data/eventman-dump-`date +'%Y-%m-%dT%H.%M.%S'`.tgz eventman
+tar cfz /data/eventman-dump-`date +'%Y-%m-%dT%H:%M:%S'`.tgz eventman