Update dependencies (issue #16)
Update dependencies (issue #16)

- io.prometheus:simpleclient ............................ 0.6.0 -> 0.7.0
- io.prometheus:simpleclient_hotspot .................... 0.6.0 -> 0.7.0
- io.prometheus:simpleclient_servlet .................... 0.6.0 -> 0.7.0

marcelmay/hadoop-hdfs-fsimage-exporter,marcelmay/hadoop-hdfs-fsimage-exporter