Plantuml-viewer on windows with Graphviz 2.44

[Pyponou]

You should add a sentence like : "With version 2.44, under Windows, you may have to run dot -c in a command line to finalize the installation." in the README (see https://plantuml.com/fr/graphviz-dot).

Because the error we get if we don't do it is strange and we don't know where the issue comes from :)