(PUP-1151) Convert to cygwin paths on windows

The curl command on windows doesn't handle windows path (C:\foo\bar), so
we need to convert these to posix paths using cygpath.
Merge branch 'feature/master/pup-1151-environment-enumeration'

* feature/master/pup-1151-environment-enumeration:
  (PUP-1151) Convert to cygwin paths on windows