Update nano-server.yml: Add missing version command

[Saibamen]

I cannot create PR in gitgitgadget, because there is no repository for Git for Windows there.

Please change your Pull Request template.

Fixes this warning:

[dscho]

Now testing C:\test\git.exe
git: '' is not a git command. See 'git --help'.

The intention of

git/.github/workflows/nano-server.yml

Line 50 in 85dac07

("C:\test\git.exe", "", 1 ),

is to verify that running git.exe with an empty argument errors out with exit code 1.

The fact that the logs show the warning might look unwanted to you, but it is very much wanted: it verifies to the reader that Git was run as intended.

In other words, the existing code works as intended, and the code introduced by this PR would not.