prepare release 7.0.0 (#520)

* prepare release 7.0.0

* Update README.md

Maven Central migration (#460)

* Maven Central migration

* Bump org.cicirello:core to 2.7.1

* Bump org.cicirello:rho-mu to 4.2.1

Merge pull request #418 from cicirello/prep-release

Prepare major release 6.0.0

Merge pull request #344 from cicirello/prep-release

Prepare release 5.1.0

Merge pull request #333 from cicirello/prep-release

Prepare release 5.0.4

Merge pull request #331 from cicirello/prep-release

Prepare release 5.0.3

Merge pull request #325 from cicirello/prep-release

Prepare release 5.0.2

Merge pull request #313 from cicirello/prep-release

Prepare release 5.0.1

Merge pull request #307 from cicirello/prep-release-5

Prepare release 5.0.0

Merge pull request #296 from cicirello/prep-release

Prepare release 4.3.1