Casing removed from paths on Windows

With a file called `TEST_capitalization.txt`
```
import pathlib
import pathlib2

print(list(pathlib.Path().glob("TEST_capitalization.txt")))
print(list(pathlib2.Path().glob("TEST_capitalization.txt")))
```

returns

```
[WindowsPath('TEST_capitalization.txt')]
[WindowsPath('test_capitalization.txt')]
```

These two should be identical, right?

It is an issue in https://github.com/mbarkhau/bumpver, where files with capital letters in the path are updated, but not staged and comitted in git.

Environment:
pathlib2 2.3.7.post1
Windows 10 Enterprise, Version 10.0.19044 Build 19044
Python 3.9.4