Update README.md with webauthn remote clientdatajson extension explainer

Author: Mo Jamal

README.md

@@ -61,6 +61,7 @@ we move them into the [Alumni section](#alumni-) below.
 | [CSS ::tooltip Pseudo Element](CSSTooltipPseudo/explainer.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/TooltipPseudo">![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/TooltipPseudo?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?template=tooltip-pseudo.md) | CSS |
 | [CSS Text Transitions & Animations](CSSTextTransitions/explainer.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/CSSTextTransitions">![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/CSSTextTransitions?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?labels=CSSTextTransitions&title=%5BCSSTextTransitions%5D+) | CSS |
 | [Enterprise Platform Authentication Broker API](PlatformAuthentication/explainer.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/Enterprise%20Platform%20Authentication">![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/PlatformAuthentication?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?template=platform-authentication-api.md) | Identity |
+| [WebAuthn `remoteClientDataJSON` Extension](WebAuthnRemoteClientDataJSON/explainer.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/WebAuthn%20RemoteclientDataJSON%20Extension">![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/WebAuthn%20RemoteclientDataJSON%20Extension?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?template=webauthn-remoteclientdatajson.md) | Identity |
 | [Handwriting CSS attribute](Handwriting/HandwritingIntentCSSValue.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/Handwriting"> ![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/Handwriting?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?assignees=adettenb&labels=Handwriting&title=%5BHandwriting%5D+Issue) | CSS |
 | [Pen Events](PenEvents/explainer.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/Pen%20Events"> ![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/Pen%20Events?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?template=pen-events.md) | Editing |
 | [Pen Action](PenAction/explainer.md) | <a href="https://github.com/MicrosoftEdge/MSEdgeExplainers/labels/Pen%20Action"> ![GitHub issues by-label](https://img.shields.io/github/issues/MicrosoftEdge/MSEdgeExplainers/Pen%20Action?label=issues)</a> | [New issue...](https://github.com/MicrosoftEdge/MSEdgeExplainers/issues/new?template=pen-action.md) | Editing |