Should eclipse IDE use tracks?

Can you all please have a try on this PR: https://github.com/snapcrafters/eclipse/pull/9
I tried to get the config and update right.

@popey PR for 2020-06: https://github.com/snapcrafters/eclipse/pull/30

Seems that is requires some changes to .travis.yml first: https://github.com/snapcrafters/eclipse/pull/31