automatically rebuild on Python update

[JBlaschke]

trafficstars

Sometimes the user needs to call ] build PyCall when the python library's version number increases (and therefore the library name changes). Is there a way to automate this?

https://github.com/JuliaPy/PyCall.jl/issues/547#issuecomment-417488942

[stevengj]

I don't know if this is possible, because once the module is loaded it is too late to precompile it again. However, it should be possible to print a clearer error message.