Shibboleth SP Windows installer updated to 3.2.2.1

[Cantor, Scott]

The Windows Service Provider installers have been updated to include libcurl 7.77.0 to address a security issue [1]. Other than those using the back-channel support, it's not terribly important, but we try and keep on top of them nonetheless.

I have also published updated CentOS 6/7 RPMs to the mirrors (allowing that CentOS 6 is EOL and officially unsupported).

-- Scott

[1] https://curl.se/docs/CVE-2021-22901.html