Thanks for the example. It fails for me.
julia> include("try.jl")
! Package pgfplots Error: The colormap `viridis' is undefined! Maybe you misspe
lled it?.
See the pgfplots package documentation for explanation.
Type H <return> for immediate help.
...
l.47 \end{axis}
Error showing value of type Axis:
ERROR: The latex command `lualatex juliaef4Hf8.tex` failed
Perhaps I need to update the pgfplots package?