RFC011: Describe how changes relate to versions

[reinkrul]

Document the Way of Working regarding how to deal with changes:

1. We use semantic versioning
2. Backwards compatible changes increment the minor version in the JSON-LD context URL, e.g.:
   { "@context": "https://nuts.nl/credentials/v1.1" }
   The JSON-LD context URI (base property inside the context) does not change, e.g.:
   { "base": "https://nuts.nl/credentials/v1"}
   This maintains backwards compatibility of integrations.
3. Breaking changes increment the major version in both the URL and URI in the base property
4. We don't use patch versions