Fix stale RFC references in SPEC.md and README

Author: benikigai

README.md

@@ -61,6 +61,5 @@ This spec is community-governed. Propose changes via GitHub issues and pull requ
 
 ## Contributing
 
-Read [CONTRIBUTING.md](./CONTRIBUTING.md) for the RFC process.  
-Open an issue to propose a change or flag a gap in the spec.  
+Open an issue to propose a change or submit a pull request.
 Contact: spec@agentwebprotocol.org

SPEC.md

@@ -361,6 +361,5 @@ A conforming agent.json file MAY:
 
 ## Contributing
 
-Changes to this spec follow the RFC process in `/RFC`.  
-Open an issue or submit a pull request to propose changes.  
+Propose changes via GitHub issues and pull requests.
 Contact: spec@agentwebprotocol.org