Add see also link to AesGcm breaking change (dotnet#8804)

Author: gewarren

xml/System.Security.Cryptography/AesGcm.xml

@@ -490,6 +490,7 @@ The <paramref name="tag" /> parameter length is not permitted by <see cref="P:Sy
         <summary>Gets the tag sizes, in bytes, supported by this instance.</summary>
         <value>The tag sizes supported by this instance: 12, 13, 14, 15, or 16 bytes (96, 104, 112, 120, or 128 bits).</value>
         <remarks>To be added.</remarks>
+        <related type="Article" href="/dotnet/core/compatibility/cryptography/8.0/aesgcm-auth-tag-size">AesGcm authentication tag size on macOS</related>
       </Docs>
     </Member>
   </Members>