Update README.md

Author: m-mohr

README.md

@@ -40,7 +40,7 @@ This repository contains a set of files formally describing the openEO Processes
 ## Process
 
 * All new processes must be added to the [`proposals`](proposals/) folder.
-* Processes will only be moved from proposals to the stable process specifications once there are at least two implementations. This doesn't require a PSC vote individually as it's not a breaking change, just an addition.
+* Processes will only be moved from proposals to the stable process specifications once there are at least two implementations and an example process in the [`openEO community examples`](https://github.com/Open-EO/openeo-community-examples/) showing it in a use case. This doesn't require a PSC vote individually as it's not a breaking change, just an addition.
 * The [`proposals`](proposals/) folder allows breaking changes without a PSC vote and without increasing the major version number (i.e. a breaking change in the proposals doesn't require us to make the next version number 2.0.0).
 * The proposals are released as experimental processes with the other processes.
 * Each release and all breaking changes in the stable process specifications must go through PSC vote.