Issue with git windows version

Hi,

Although I am a vim beginner, I quickly came across vim-plug. I noticed that the plugin encounters problems of following type in some environments.
```
Fehler beim Ausführen von "function 21_install[1]..21_update_impl[62]..21_git_version_requirement[2]..21_system[30]..function 21_install[1]..21_update_impl[62]..21_g
it_version_requirement[2]..21_system":
Zeile 24:
E484: Can't open file C:\Users\KONSTA~1.PAP\AppData\Local\Temp\VBVA3E4.tmp
Fehler beim Ausführen von "function 21_install[1]..21_update_impl[62]..21_git_version_requirement":
Zeile 2:
E171: Missing :endif
Fehler beim Ausführen von "function 21_install[1]..21_update_impl":
Zeile 62:
E171: Missing :endif
```

I suspect it has something to do with version handling in the function s:git_version_requirement or s:version_requirement.
For this you should know that the git version output looks like this.
```
git version --build-options

git version 2.33.1.windows.1
cpu: x86_64
built from commit: 05d80adb775077d673fab685009ede4a1003ed92
sizeof-long: 4
sizeof-size_t: 8
shell-path: /bin/sh
feature: fsmonitor--daemon
```