glrd: update documentation for semantic versioning

[yeoldegrove]

What happened:

With v4.0.0 we introduced semantic versioning but missed documenting this in e.g. the README.

What you expected to happen:

Docs shall be updated.

[yeoldegrove]

The README actually includes major.minor.patch versions already but many examples use a major version < 2017 which does not use the new semantic versioning.
As soon as a new major with semantic versioning comes out, the examples should be updated.