Vim is not available as external editor on windows

Thanks for `gitui`, it makes my daily life easier=)

There is, however, one thing that seems break my current flow - I can not launch vim from within gitui.

**Describe the bug**
Vim is not available as external editor

**To Reproduce**
Steps to reproduce the behavior:
1. Navigate to a repo with modified files, run `gitui`
2. Chose a file with modifications
3. Hit 'e' button to edit this file
4. A "popup" appears:
```
failed to launch editor:
"vim": program not found
```
Same bug observed when trying to '^e'dit commit message in external editor.

**Expected behavior**
A `vim` instance with selected file loaded.

**Context (please complete the following information):**
- OS/Distro + Version: win10 (build 21H2-19044.1889)
- GitUI Version 0.21.0
- Running in `WindowsTerminal` and `pwsh-7.2.6`
- both `vim` and `gitui` are installed via `chocolatey`

**Additional context**
`vim` is present in path:
```console
PS1> where.exe vim
C:\Windows\vim.bat
```
and `git` is configured to use `vim`
```console
git config -l | rg editor
core.editor=vim
```