clang++ version not working anymore in wiki doc

[JBacc1]

It seems, on page: https://github.com/mapnik/mapnik/wiki/UbuntuInstallation, Install Mapnik from source,
that: export CXX="clang++-3.8" && export CC="clang-3.8"
should now be replaced by: export CXX="clang++-10" && export CC="clang-10"

[artemp]

@JBacc1 - the page is outdated and needs some revamping, cheers.

[JBacc1]

Perhaps write it on top of the page: "This page is old and not up to date"? At least you won't expect it to work that fine?