deprication warnings

[Heidistein]

As I am cleaning my puppet code, I came across deprecation warnings, emitted by stdlib, originating from sssd.
/etc/puppetlabs/code/environments/test/modules/sssd/manifests/init.pp line 73 calls 'validate_re', which is depricated: https://github.com/puppetlabs/puppetlabs-stdlib#validate_re

Could be "fixed" using something like:
validate_legacy("Optional[String]", "validate_re", "Value to be validated", ["."])
which would break puppet3 compatibility.

Low priority, imho.

[ghoneycutt]

In issue #37 I asked for a v1.0.0 release. After that, suggest a v2.0.0 that drops support for Puppet v3 and implements data types and related Puppet v4 only features, which will stop these deprecation warnings.

[edestecd]

At some point we need to depreciate puppet 3 support.
It was EOL Dec 2016, so any time now.