Update base image to tomcat:8.5-jre8

Previous base image, tomcat:8.0-jre8, is no longer available in
Dockerhub. This commit upgrade the base image to tomcat:8.5-jre8.

library/geonetwork

@@ -5,7 +5,7 @@ GitRepo: https://github.com/geonetwork/docker-geonetwork
 Architectures: amd64, arm32v5, arm32v7, arm64v8, i386, ppc64le, s390x
 
 Tags: 3.4.4, 3.4, latest
-GitCommit: 4e77623ad6a2cfb94c3c57e3558815e44936adae
+GitCommit: 2d357e39f107bf2527b9b4b396084a759c245b72
 Directory: 3.4.4
 
 Tags: 3.4.4-postgres, 3.4-postgres, postgres