doc: add news issue for Diagnostics WG

Signed-off-by: Michael Dawson <mdawson@devrus.com>

PR-URL: nodejs#49306
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>

doc/contributing/sharing-project-news.md

@@ -31,3 +31,4 @@ that promotes a specific company or commercial interest.
 * [node-api/node-addon-api](https://github.com/nodejs/abi-stable-node/issues/446).
 * [uvwasi](https://github.com/nodejs/uvwasi/issues/201).
 * [security-team](https://github.com/nodejs/security-wg/issues/1006).
+* [diagnostics team](https://github.com/nodejs/diagnostics/issues/619).