Dependency on sbt-assembly refers to an old version

[julienrf]

While investigating which packages of the Scala ecosystem depend on artifacts published to the sbt community repository (see this discussion), I’ve noticed that this project depends on old versions of sbt-assembly, which are not available on Maven Central.

See the references here:

https://github.com/kyleu/projectile/blob/ed9cde0e5a1d2e86caab0f11e0f037e15e8c95ba/project/SbtExportPlugin.scala#L15

and here:

https://github.com/kyleu/projectile/blob/ed9cde0e5a1d2e86caab0f11e0f037e15e8c95ba/project/plugins.sbt#L21

I recommend bumping the dependency to use a version that is available on Maven Central.