Update dependencies (issue #30)
Update dependencies (issue #30)

- org.assertj:assertj-core ................. 3.16.0 -> 3.16.1

- io.prometheus:simpleclient ............... 0.8.1 -> 0.9.0
- io.prometheus:simpleclient_hotspot ....... 0.8.1 -> 0.9.0
- io.prometheus:simpleclient_httpserver .... 0.8.1 -> 0.9.0

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