Add links to UW Madison slides (#621)

Fixes #478

Author: ashwinvis

instructors/slides/UW-Madison_list-of-slides.md

@@ -0,0 +1,5 @@
+# Presentations from UW Madison
+
+- 2023: See [here](./23-05_UW-Madison_IntroDL-Slides.pdf) for an older version of the slides.
+- 2024: See [here (on Google Docs)](https://docs.google.com/presentation/d/1uT4uvfWrpvrrQEFp84PGfAQ2r9Ylqx8tbwiVFuGfEao/edit?usp=sharing) for an updated version of the slides.
+