Important bug fix to 4.0.0 authentication

There was a bug in the `NEO4J_AUTH` logic that meant the default password wasn't being set if `NEO4J_AUTH` was empty. This is fixed, and I feel is sufficiently important that we should update 4.0.0 tag (the actual neo4j source stays the same, just the docker-entrypoint wrapper is changed).

library/neo4j

@@ -10,12 +10,12 @@ Maintainers: Ben Butler-Cole <[email protected]> (@benbc),
 
 Tags: 4.0.0, 4.0, latest
 GitRepo: https://github.com/neo4j/docker-neo4j-publish.git
-GitCommit: 99d2f403da30850cfd2b7d04acd484b168ef6cb1
+GitCommit: 685fb314ef8e451217b6806028b9ac4dbf44d3fc
 Directory: 4.0.0/community
 
 Tags: 4.0.0-enterprise, 4.0-enterprise, enterprise
 GitRepo: https://github.com/neo4j/docker-neo4j-publish.git
-GitCommit: 99d2f403da30850cfd2b7d04acd484b168ef6cb1
+GitCommit: 685fb314ef8e451217b6806028b9ac4dbf44d3fc
 Directory: 4.0.0/enterprise