The URL to download the latest build has changed with the recent upgrade to Nexus 3.x

[waynebeaton]

See #534

Based on my quick read of the documentation, review of the repository changes, and some trial and error, I believe that the correct URL should be this:

https://repo.eclipse.org/service/rest/v1/search/assets/download?sort=version&repository=dash-maven2-releases&maven.groupId=org.eclipse.dash&maven.artifactId=org.eclipse.dash.licenses&maven.extension=jar

I've updated the README accordingly.

I believe that this impacts Eclipse Dash work maintained by @gomes89 @marcdumais-work

Any thoughts on how we can make this URL more resilient? I suppose that I could set up a redirect somewhere...