- changed EFDI proto link to current github repository and added some…

… info how to get access. (DKE-Data#20)

OK

README.adoc

@@ -24,7 +24,8 @@ image::https://travis-ci.com/DKE-Data/agrirouter-api-protobuf-definitions.svg?br
 Here are some external resources for the development:
 
 * https://my-agrirouter.com[My Agrirouter Website]
-* https://www.aef-online.org[EFDI Protobuf Definition]
+* https://github.com/aefev/fmisei-spec/blob/master/proto-v3-grpc/iso11783-10.proto[EFDI Protobuf Definition (working draft)] currently only available for AEF members - will be pulished when the working draft of the guideline documents is finished.
+If you are AEF member and do not have access, please ask the AEF office to grant you access to the repository.
 
 == Language specific compiling of the `*.proto` definitions