Corrected NABDConf video

Author: seanlaw

docs/motivation.rst

@@ -7,5 +7,5 @@ The following video from May 2019, provides the background and motivation for de
 .. raw:: html
 
  <div style="position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; height: auto;">
- <iframe src="https://www.youtube.com/embed/ep6yBul2Sq8" frameborder="0" allowfullscreen style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
- </div>
+ <iframe src="https://www.youtube.com/embed/WvaBPSeA_JA" frameborder="0" allowfullscreen style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;"></iframe>
+ </div>