"cabal v2-install --lib" uses the wrong directory for the global package environment on Windows

[aboichis]

Describe the bug
cabal writes the package environment file in the directory returned by getHomeDirectory.
GHC uses getAppUserDataDirectory.
These are the same on Linux, but different on Windows (%HOMEPATH% and %APPDATA% respectively)

To Reproduce
Steps to reproduce the behavior:

cabal v2-install --lib vector
ghci

Expected behavior
The package environment file should be created in the correct directory and ghci should load it on startup.

System information

• Windows 10
• cabal 3.0.0.0, ghc 8.6.5

[vituscze]

I can't test the change right now, but something like this should make it match the GHC defaults: https://github.com/vituscze/cabal/commit/84a97d9bce6b725c70e6a4de3fb808c60986a2ff