Update video to SciPy 2020 (#196)

Author: jrbourbeau

README.md

@@ -1,7 +1,7 @@
 # Dask Tutorial
 
 This tutorial was last given at SciPy 2020 which was a virtual conference.
-[A video of the SciPy 2018 tutorial is available online](https://www.youtube.com/watch?v=mqdglv9GnM8).
+[A video of the SciPy 2020 tutorial is available online](https://www.youtube.com/watch?v=EybGGLbLipI).
 
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