Use newer sbt-osgi for main branch

[mdedetrich]

With #745 we ended up creating a patched sbt-osgi v0.9.4 which contained the corrupted jar fix that is now used for both main and 1.0.x. While there is a strong argument that for the 1.0.x branch of Pekko we should leave sbt-osgi on 0.9.4-INVALID-CEN-JAR-PATCH indefinitly, for main we ideally should be using the newer sbt-osgi because if we find more issues with sbt-osgi we won't be able to use it until we fix the regression that is now present in the latest version of sbt-osgi. Its better that we nip this in the bud sooner rather than later since we have some breathing space now.

As can be seen at sbt/sbt-osgi#93 (comment), there are apparently fixes for the duplicate classes being placed in the osgi package creating the error described at #745 (comment) so we should apply these fixes + create new releases of sbt-osgi so that we can properly solve the regression as part of sbt/sbt-osgi#93 (comment) .

Pinging @pjfanning @lefou @romainreuillon

[mdedetrich]

Did an investigation upstream at sbt/sbt-osgi#102