What's Changed
Added graph validation with SHACL, specifically added:
1. A SHACL shape graph with constraints that ensure a KG's executability.
2. The sheXer Python script that was initially used to create the basis for the above shape graph.
3. KG validation step (using pySHACL and the above shape graph) during KG creation and before KG execution.
**Full Changelog**: https://github.com/boschresearch/ExeKGLib/compare/2.0.4...2.1.1