[SSSD] [sssd PR#181][opened] README.md: Point to our releases on pagure

[jhrozek]

   URL: https://github.com/SSSD/sssd/pull/181
Author: jhrozek
 Title: #181: README.md: Point to our releases on pagure
Action: opened

PR body:
"""
Since the README.md is more or less what the wiki front page used to be,
it makes sense, especially for Github users, to point to our releases
from README.md
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/181/head:pr181
git checkout pr181