Implement a compatibility matrix between the API and the Spec

#### Reason/Context
The Parser-API is built for being used in the long-term. Most of AsyncAPI spec breaking changes won't affect this API.
However, there are always changes in the AsyncAPI spec that will need to be reflected into this API, generating patches, minors or less expected major versions.

This is why I think we should create and maintain a compatibility matrix between the API and the Spec.
We already discussed about this in the past [here](https://github.com/asyncapi/shape-up-process/issues/95#issuecomment-824814114), where some proposals were written down as well.

#### Description
Based on https://github.com/asyncapi/shape-up-process/issues/95#issuecomment-824814114, also including further comments, a table similar to the following would be included in this repo README (or where documentation goes).
Inspiration from https://github.com/kubernetes/kube-state-metrics/blob/master/README.md#compatibility-matrix.

Parser API|Spec v2.0.0|Spec v2.1.0|Spec v2.2.0|Spec v3.0.0
---|---|---|---|---
v1.0.0 | ✓ | ✓ | - | X

- `✓` Fully supported version.
- `-` The AsyncAPI Spec version has features the Parser API can't use but the rest are fully supported.
- `X` Not supported version.