Motivation:
I'm performing some security research against various Java-based projects as a part of the new [GitHub Security Lab](https://securitylab.github.com/) Bug Bounty program.
Currently, LGTM.com can't create a CodeQL database for this project because of missing dependencies. This fixes the build so it works correctly.
The maintainers may also want to consider enabling the free [LGTM Integration](https://github.com/marketplace/lgtm) once this PR is merged.
Modification:
Adds a `.lgtm.yml` with a tested configuration:
A successful build can be found here:
https://lgtm.com/logs/6695df28f6b2b1d3fd4d03e968b600a3e9c9aecf/lang:java
Result:
LGTM.com will be able to process this repository to create a CodeQL database.
