Windows support

[rruiter87]

When I try to use this under Windows I get the following error:

Formats XML files........................................................Failed
- hook id: format-xmllint
- exit code: 1

Executable `/bin/sh` not found

I guess it shouldn't work on Windows. Are there any plans to make it work on Windows?

[Ryanf55]

If it were ported to python, would that work?

[rruiter87]

Yes, see https://github.com/pcdshub/pre-commit-hooks/blob/master/pre_commit_hooks/xml_format.py