Update README.md

Author: michielbdejong

README.md

@@ -24,7 +24,7 @@ interoperably on your PDS.
 - Michiel de Jong [@michielbdejong](https://github.com/michielbdejong)
 - Yvo Brevoort [@ylebre](https://github.com/ylebre)
 
-## Watch a video
+## Listen to a Lecture
 A guest lecture about PDS Interop, which Michiel de Jong gave at CERN in September 2021, can be viewed [here](https://cds.cern.ch/record/2782493).
 
 ## Projects