README: add link to GopherCon Debugging Treasure Hunt presentation

Updates #1930

Change-Id: Iab53ccb393ace5d3bc353441d2585287fa163cec
GitHub-Last-Rev: 1e62645
GitHub-Pull-Request: #1946
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/372416
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Polina Sokolova <polina@google.com>

README.md

@@ -16,6 +16,8 @@ We recommend switching your remote attach configurations in `launch.json` to use
 `"debugAdapter":"dlv-dap"` now to verify that this works for you.
 Please [file a new issue](https://github.com/golang/vscode-go/issues/new/choose) if you encounter any problems.
 
+📣📣 Watch [Debugging Treasure Hunt](https://youtu.be/Gcp2ACyCadA?t=16211) from [GopherCon 2021](https://www.gophercon.com/) for a fun take on a debugging demo with VS Code Go and Delve DAP.
+
 ## Quick Start
 
 Welcome! 👋🏻<br/>