Not working for git log -p --graph 

I tried this package for Windows and it looked like it's not working.

Works for `git log -p` but does not work for `git log -p --graph`

I tried that in Linux too but it was same.

the perl version from git was working for both BTW

```
git version 2.33.1.windows.1
git version 2.20.1 (linux)

diff-highlight-1.2.0
```