Update README.md

[TilmanTheile]

Deleted:
OAuth 2.0 Dynamic Client Registration Protocol
OAuth 2.0 Dynamic Client Registration Management Protocol

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Checklist

• I have read the contributing guidelines
• I have read the security policy
• I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security
  vulnerability, I confirm that I got green light (please contact [email protected]) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

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[CLAassistant]

All committers have signed the CLA.