Upgrade to Scala 2.12.x

[refond]

Minimal changes require test framework change.
Using actively used and maintained org.scalatest.

Keep flying-saucer 9.0.x, moving to 9.1.x requires
more work.

[EECOLOR]

Hi @refond,

thank you for the pull request! Unfortunately we don't maintain this library anymore. As a matter of fact, all libraries in kaliber-scala are no longer maintained by Kaliber. We rely purely on the community for updates.

Our local maven repository has been transformed in a static site that just serves the previously created packages but we can not release new versions anymore. The more popular libraries have been changed to release to bintray (and maven central): https://github.com/kaliber-scala/play-s3/pull/83/files

So, we have 2 options here:

1. I give you write access to the repository and bintray organisation so you can release the package as part of the kaliber-scala eco-system
2. You fork the repository and handle distribution yourself. In this case I am happy to change the readme to point to your repo.

[refond]

Hi @EECOLOR,
I'll try to go with your proposal n°1, although I have no experience releasing package to public repositories and be thankful if you head me to any guidelines you have for your package release process.
I observed you use https://github.com/gseitz/sbt-release, which seems to have moved to https://github.com/sbt/sbt-release

[EECOLOR]

@refond I added you as a collaborator to the repository. Let me know your bintray username so I can add you as a member to the kaliber-scala organisation

[refond]

@EECOLOR my bintray username is identical to github one: refond

[EECOLOR]

@refond Great, let me know when you have accepted the invite so I can give you Admin permissions

[EECOLOR]

@refond You have admin permissions, let me know if you need help

[refond]

@EECOLOR Thank you, I'll come back to you if needed.

[ceecer1]

any updates guys ?

[EECOLOR]

@ceecer1 I do not have an update for you. Maybe @refond has one.

[LeonhardtDavid]

@ceecer1 we did a fork and published it to maven central. If you want to take a look:
https://github.com/viajobien/scala-pdf

[EECOLOR]

@LeonhardtDavid if you want I can mention your repository in the readme as the one that is being maintained.