apt just got broken on my WSL installation.
I didn’t dig through much, but it started once I upgraded to Ubuntu 18.04.

Here the error I’m getting when trying to install new packages:

apt: error while loading shared libraries: libapt-private.so.0.0: cannot open shared object file: No such file or directory

To fix the above issue, fastest way I found is to reinstall apt package for Ubuntu bionic release (18.04).

1) Download apt deb package

wget http://mirrors.kernel.org/ubuntu/pool/main/a/apt/apt_1.6.12_amd64.deb

2) Install it with dpkg

dpkg -i apt_1.6.12_amd64.deb

It should then work again like a breeze.