Update .NET CHANGELOG for 4.0 beta2 release
+v4.0.0b2
+========
+ * (on behalf of Artur Nebot) Set EdgeOptions to start Chromium-based Edge
+ by default. Fixes issue #9262.
+ * Added support for CDP in Firefox. This currently only works for Firefox
+ Nightly. To use this feature, set the EnableDevToolsProtocol property of
+ FirefoxOptions to true.
+ * Fixed network interception for use with browsers that support CDP.
+
v4.0.0b1
========
* Added ability to listen for JavaScript exceptions and callbacks for
