Adding a spec to the Cowin Payload

cowin.html

@@ -103,7 +103,7 @@ DcJqR5clbAYlO9lHmvb4lsPLZHjugQ==
             </div>
             <div class="full-div">
                 <div class="two-quarter">
-                    <h4>PCF's Format</h4>
+                    <h4>PCF's Format (<a href='https://github.com/Path-Check/paper-cred/blob/main/payloads/cowin.1.md'>Spec</a>)</h4>
                     <canvas id="qr-divoc-code"></canvas><br/>
                     <pre id="qr-divoc-result"></pre>
                     <pre id="qr-divoc-verified"></pre>