* github/build: verify javadoc validity
* github/build: stop testing against JDK 8
* github/build: test against JDK 16 and 17-ea
Drop testing against JDK 15
* github/deploy: remove graphviz
* github.deploy: nexus username is not a secret
* github/settings: nexus username is not a secret
* github/deploy: publish javadoc
To: https://kemitix.github.io/wiser-assertions/
* github/build: upgrade setup-java action to 2.1.0
* github/deploy: upgrade setup-java action to 2.1.0
