Adding versions to the provider POMs

This is necessary to create a provider specific release. When creating a provider specific release, the artifact version of the single provider is incremented, then a special tag is created to indicate the change only refers to that one provider.

In the existing case, there are no versions specified for provider libraries. That causes maven to inherit the version from the parent, which in turn forces all provider libraries to have the same version. We need to explicitly set the versions in order to have different ones per provider.