Update conferences.md (beta docs) (#5615)

* Update conferences.md (beta docs)

Add Reactathon 2023 to the beta docs

* fix syntax error

beta/src/content/community/conferences.md

@@ -10,6 +10,11 @@ Do you know of a local React.js conference? Add it here! (Please keep the list c
 
 ## Upcoming Conferences {/*upcoming-conferences*/}
 
+### Reactathon 2023 {/*reactathon-2023*/}
+May 2 - 3, 2023. San Francisco, CA, USA
+
+[Website](https://reactathon.com) - [Twitter](https://twitter.com/reactathon) - [YouTube](https://www.youtube.com/realworldreact)
+
 ### RemixConf 2023 {/*remixconf-2023*/}
 May, 2023. Salt Lake City, UT