Cross-publish stages each Scala-version to a separate staging repository

[ThijsBroersen]

When I cross-publish with '+publishSigned' the results are staged in multiple staging repositories (one for each Scala-version). Sometimes it is staged in a single repository. This seems ambiguous.
If I run 'sonatypeRelease' it fails when multi-repositories are found, but putting 'sonatypeReleaseAll' in my travis-build is not desired as there can be staging repositories (other builds, other projects).

I looked in the source code and tried some manual testing. It looks like 'sonatypeStagingRepositoryProfile' keeps a reference to a staging-repository. Is it possible to keep multiple references and have 'sonatypeRelease' promote and close this list of staging-repositories?

[xerial]

I guess #77 is related.

[ThijsBroersen]

I guess #77 is related.

Not sure, but I apologize I forgot to mention similar issues. E.g. #66 #73 and #49 where is reported about multiple parallel publishSigned commands somtimes publish to the same repository.

[xerial]

@ThijsBroersen I've redesigned the release flow. By using the flow described here https://github.com/xerial/sbt-sonatype#multi-module-projects, it should be possible to use the same staging repository to publish.

This feature is added since sbt-sonatype 3.0