[SSSD] Announcing SSSD 2.6.1

[Pavel Březina]

# SSSD 2.6.1

The SSSD team is proud to announce the release of version 2.6.1 of the
System Security Services Daemon. The tarball can be downloaded from:
      https://github.com/SSSD/sssd/releases/tag/2.6.1

See the full release notes at:
      https://sssd.io/release-notes/sssd-2.6.1.html

RPM packages will be made available for Fedora shortly.

## Feedback

Please provide comments, bugs and other feedback via the sssd-devel
or sssd-users mailing lists:
      https://lists.fedorahosted.org/mailman/listinfo/sssd-devel
      https://lists.fedorahosted.org/mailman/listinfo/sssd-users

## Highlights

### New features

* New infopipe method `FindByValidCertificate()` which accepts the 
certificate as input, validates it against configured CAs, and outputs 
the user path on success. This is similar to the existing 
`FindByCertificate()`, but that does not do any trust validation.

### Packaging changes

* `subid ranges` support was enabled by default.

### Configuration changes

* Default value of `ssh_hash_known_hosts` setting was changed to false 
for the sake of consistency with OpenSSH that does not hash host names 
by default.