Add the ptSrcFieldTD as a 'functional' dependency for the virtual sensing topic in its README.md

Virtual Sensing/README.md

@@ -24,6 +24,7 @@ There are no functional dependencies, however, the implementations are based on
       - `virtMicGeo()`
   - Sound Fields
     - `ptSrcField()`
+    - `ptSrcFieldTD()`
     - `planeWave()`
 
 ## Examples