(FACT-728) Update Windows OS release resolution for > 6.2.x kernels

Currently, Facter only knows how to deal with Windows kernels
up to 6.2.x for parsing out the operating system release value.
Windows 8.1, 2012 R2 and 10 use kernel versions 6.3.x and 6.4.x
which cause Facter to fall back to reporting the kernel version
as the operating system release, instead of the strings "8", "10"
or "2012 R2" as it should.

This commit adds a check for kernel versions starting with "6.3"
or "6.4" to resolve this issue.
Merge pull request #805 from whopper/fact-728/win_release_6.x

(FACT-728) Update Windows OS release resolution for > 6.2.x kernels