Versioning in the docs

[ChrisRackauckas]

We should probably explain with each package installation what version of Julia is recommended/required.

More thoughts: https://discourse.julialang.org/t/universal-differential-equations/89093/7

[ArnoStrouwen]

Something like this?
https://arnostrouwen.github.io/ArnoTester.jl/dev/

[ChrisRackauckas]

oh that's really nice!

[ArnoStrouwen]

This has been implemented.