support configuration of plantUML server

[FrVaBe]

Markdown PDF works great but it seems to always use the default plantUML server configured in markdown-it-plantuml. This server only accepts a certain number of requests per document. In documents with a large number of diagrams, not all diagrams are created. Instead, we have this warning in the document:

The use of an own (local) PlantUML server usually helps here. Therefore this is a feature request to make the Plant UML Server address configurable.

See also a corresponding Issue #12 in the markdown-it-plantuml repository, but I think it is missplaced there and belongs to this project here.

[yzane]

Please upgrade Markdown PDF to ver1.4.4 and try.

[FrVaBe]

Thanks @yzane - that works just fine now!

Still looking for a possibility to have a nice preview in VS Code. Even the Markdown Preview Enhanced Plugin does not manage to show plantuml diagrams which are simple given as @startuml ... @enduml code snippets. And the output of the preview looks very different to the pdf output. Thus this is no alternative for me. But that is another story