update contribute.md using site: ... for merge-request workflow

docs/get-involved/contribute.md

@@ -20,10 +20,11 @@ This is how you can actually make a difference:
 The flowchart below illustrates the Merge Request workflow, along with the commands used at each stage.
 
 <figure>
-  <img src="../../assets/images/merge_request_workflow.png" alt="merge-request" width="500" style="border: 2px solid black;">
+  <img src="site:assets/images/merge_request_workflow.png" alt="merge-request" width="500" style="border: 2px solid black;">
   <figcaption>Merge request workflow</figcaption>
 </figure>
 
+
 You cloned/forked the UNICADO Package successfully acc. to [Get Source Code](get-source-code.md). Nice! You want to make a change, e.g. fixing a bug or creating a new feature, so you create a *issue* (see also [types of contribution](#contributions)). Then you :point_up: create a feature branch, change the code and create a merge request (here a [how to](merge-request.md)). An automatic CI/CD pipeline is triggered, which helps your selected reviewer to make sure that request is ok. If it is accepted and ready-to-land :airplane:, the documentation is automatically updated. Nicely done :+1:
 
 ## Types of contribution {#contributions}