Importing local Python module fails in Julia 1.4?

Hi, I have the following code
```julia
using PyCall
pushfirst!(PyVector(pyimport("sys")."path"), srcdir())
pypsd = pyimport("PSD")
```
`srcdir()` is a *directory* that points to a *folder* which includes a *file* `PSD.jl`.I was using this code about 3 months ago and it worked fine for me.

Unfortunately it doesn't work anymore, even though there was absolutely nothing changed in my source code:
```
ERROR: LoadError: PyCall.PyError("PyImport_ImportModule\n\nThe Python package PSD could not be found by pyimport. Usually this means\nthat you did not install PSD in the Python version being u...
```

The only difference with the past I can think of is that I'm now using a more recent Julia version, 1.4. Has the way of including local modules changed? I've looked at the readme, but I only found a note that PyCall.jl doesn't include current directory by default, but this is not my case.

Reproduce el fallo con la secuencia mostrada de `PyCall`, `pyimport("sys")`, `sys.path`, `srcdir()` y `PSD` en Julia 1.4. Empieza comprobando cómo se exponen a Python el directorio local y el módulo `PSD`, y después compara el comportamiento con la configuración que funcionaba anteriormente. Se considera terminado cuando el módulo local `PSD` se importa correctamente o el problema queda aclarado con la configuración necesaria.

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