Update nexus3.json

public/v2/apps/nexus3.json

@@ -1,7 +1,7 @@
 {
     "captainVersion": "2",
     "documentation": "Taken from https://hub.docker.com/r/sonatype/nexus3/",
-    "displayName": "",
+    "displayName": "Nexus3",
     "description": "Nexus is a repository manager. It allows you to proxy, collect, and manage your dependencies",
     "dockerCompose": {
         "version": "3.3",
@@ -30,4 +30,4 @@
             "description": "Additional tags can be found here: https://hub.docker.com/r/sonatype/nexus3/tags"
         }
     ]
-}
+}