Core - Update CefSettingsBase.ProductVersion

Change to use the user_agent_product property, as this is a breaking change and the `90-pre` release has already happened
wait we won't rename the property until version 91

https://bitbucket.org/chromiumembedded/cef/commits/02ae4597d8b6c895e46891a7596cf5fa1fe15df8#Linclude/internal/cef_types.hT309

Issue #3530

Author: amaitland

CefSharp.Core.Runtime/CefSettingsBase.h

@@ -277,13 +277,13 @@ namespace CefSharp
 
             /// <summary>
             /// Value that will be inserted as the product portion of the default User-Agent string. If empty the Chromium product version
-            /// will be used. If UserAgent is specified this value will be ignored. Also configurable using the "product-version" command-
+            /// will be used. If UserAgent is specified this value will be ignored. Also configurable using the "user-agent-product" command-
             /// line switch.
             /// </summary>
             property String^ ProductVersion
             {
-                String^ get() { return StringUtils::ToClr(_cefSettings->product_version); }
-                void set(String^ value) { StringUtils::AssignNativeFromClr(_cefSettings->product_version, value); }
+                String^ get() { return StringUtils::ToClr(_cefSettings->user_agent_product); }
+                void set(String^ value) { StringUtils::AssignNativeFromClr(_cefSettings->user_agent_product, value); }
             }
 
             /// <summary>