Duty examples are written wrong

[woutslabbinck]

https://github.com/SolidLabResearch/ODRL-Compliance-Report-Model/blob/main/Duty-Rule-Example.md?plain=1#L36
https://github.com/SolidLabResearch/ODRL-Compliance-Report-Model/blob/main/Duty-Rule-Example.md?plain=1#L60
https://github.com/SolidLabResearch/ODRL-Compliance-Report-Model/blob/main/Duty-Rule-Example.md?plain=1#L84
prohibition there should be duty