Add edge to compatibilitytable

Author: coryjthompson

README.md

@@ -273,6 +273,20 @@ This method returns a Dictionary<string, string> intented to be headers of a web
    </td>
    </tr>
 
+   <tr>
+   <td>Edge</td>
+
+   <!-- Push without payloads support-->
+   <td>✓ v17+</td>
+
+   <!-- Push with payload support -->
+   <td>✓ v17+</td>
+
+   <!-- VAPID Support -->
+   <td>✓ v17+</td>
+
+   <td></td>
+   </tr>
    <tr>
    <td>Safari</td>