How to save a GraphViz graph?

[jpsamaroo]

I can't get the examples from the tests to work on 1.11, I get:

julia> show(IOBuffer(), MIME"image/png"(), dot"")
ERROR: MethodError: no method matching show(::IOBuffer, ::MIME{Symbol("image/png")}, ::GraphViz.Graph)
The function `show` exists, but no method is defined for this combination of argument types.