Restore Java 8 compatibility
Xtext (via EMF) has some open version ranges in its transitive dependencies. These ranges recently started picking up equinox.common versions that are not compatible with Java 8. The plugin now automatically corrects these versions back down.
Note: There will be no more releases for the IDEA and Android portions of the plugin, because IDEA support for Xtext/Xtend has been unmaintained for a long time, so supporting it in the plugin no longer makes sense.