doc: add minutes for meeting 2021-04-21

Fixes: nodejs#474

wg-meetings/2021-04-21.md

@@ -0,0 +1,42 @@
+# Node.js  Diagnostics WorkGroup Meeting 2021-04-21
+
+## Links
+
+* **Recording**: https://www.youtube.com/watch?v=QmsBzrDo6w8
+* **GitHub Issue**: https://github.com/nodejs/diagnostics/issues/474
+* **Minutes Google Doc**: https://docs.google.com/document/d/1fFaniF66dpt4kHmnQTq3Qbuyg-WCcMYfK5jJYwbnG6M/edit
+
+## Present
+
+* Diagnostics team: @nodejs/diagnostics
+* Rafael Gonzaga (@rafaelgss)
+* Gireesh Punathil (@gireeshpunathil)
+* MIchael Dawson (@mhdawson)
+* Stephen Belanger (@Qard)
+
+
+## Agenda
+
+## Announcements
+
+*Extracted from **diag-agenda** labelled issues and pull requests from the **nodejs org** prior to the meeting.
+
+### nodejs/node
+
+* async_hooks: use new v8::Context PromiseHook API [#36394](https://github.com/nodejs/node/pull/36394)
+  * upstream v8 changes landed, this PR needs an update.
+
+### nodejs/diagnostics
+
+* Identify async_hooks use cases beyond AsyncLocalStorage [#437](https://github.com/nodejs/diagnostics/issues/437)
+  * still needs to devise action plans for collecting more inputs.
+  * Micheal: surveys have been generally useful to collect user input.
+
+## Q&A, Other
+
+## Upcoming Meetings
+
+* **Node.js Foundation Calendar**: <https://nodejs.org/calendar>
+
+Click `+GoogleCalendar` at the bottom right to add to your own Google calendar.
+