upgrade vertx and pac4j

[vsct-jburet]

This pull request upgrades Vert.x (see #300) and pac4j.
I have removed the Rx dependency.

I created this PR because I need to upgrade Vert.x in a project that depends on vertx-pac4j.

HTH

[leleuj]

It's looks very good to me. Though, there are some blocking issues:

• please upgrade the version to 7.0.0-SNAPSHOT in the pom.xml file as it's a new major version
• change the JDK version to 17 in the pom.xml file but in the .github/workflows/ci.yml file as well
• update the README.md file
• checks that the build passes on the CI.

[vsct-jburet]

@leleuj it should be ok now

[leleuj]

I created a 6.0.x branch for the current version and merged your changes in the master.

Thank you very much for your contribution.

Can you update the https://github.com/pac4j/vertx-pac4j-demo before I cut the release?

[vsct-jburet]

@leleuj done pac4j/vertx-pac4j-demo#264

[leleuj]

Thanks. It's merged. I will cut the release ASAP.

[leleuj]

The release has been cut and is now available in the Maven central repo.