Point to new specification document adoc

Author: pmai

README.md

@@ -3,7 +3,7 @@
 [![ProtoBuf CI Builds](https://github.com/OpenSimulationInterface/osi-sensor-model-packaging/actions/workflows/protobuf.yml/badge.svg)](https://github.com/OpenSimulationInterface/osi-sensor-model-packaging/actions/workflows/protobuf.yml)
 
 OSI Sensor Model Packaging specifies ways in which models (like e.g. environmental effect models, sensor models and logical models) using the [Open Simulation Interface (OSI)][] are to be packaged for their use in simulation environments using FMI 2.0.
-The specification can be found in the [doc/specification.rst](doc/specification.rst) document in this repository.
+The specification can be found in the [doc/osi-sensor-model-packaging_spec.adoc](doc/osi-sensor-model-packaging_spec.adoc) document in this repository.
 
 For more detailed information see the [official documentation](https://opensimulationinterface.github.io/osi-documentation/osi-sensor-model-packaging/README.html).