test tycho 5

[martinlippert]

As mentioned in the release notes for the recent Tyco release, we need to prepare to upgrade to Tycho 5 sometime soon. In order to provide feedback, we should give the latest tycho 5 snapshot builds a try.

https://github.com/eclipse-tycho/tycho/blob/tycho-4.0.13/RELEASE_NOTES.md

[martinlippert]

Meanwhile, Tycho 5 got released, so we could test switching to that release instead of early snapshot builds.