how to make sure certain version of package is fetched

I'm checking `seaborn.jl`s' `pandas.jl`s' code and the following line basically handles importing logic

```julia
copy!(seaborn, pyimport_conda("seaborn", "seaborn"))
```

How do you make sure that it doesn't just get any version of `seaborn` but a specific version. Let's say `0.11.1` instead of `0.11.2`

Start by reading the seaborn.jl and pandas.jl code around the pyimport_conda("seaborn", "seaborn") call. Check the PyCall package-fetching behavior for how a requested package version is represented, and document the supported way to obtain seaborn 0.11.1 rather than 0.11.2.

Escrito por el modelo de indexación a partir del texto del issue.