Maven 3.0.5

This is the same formula in Homebrew before it was replaced by the newer 3.1.0
release.

There seems to be an outstanding issue in Maven with regards to their 
migration from Sonatype Aether to Eclipse Aether, which causes projects to not
build with 3.1.0.

https://cwiki.apache.org/confluence/display/MAVEN/AetherClassNotFound