MINOR: updating release notes with documentation describing changes t…

…o ReportAdmin and SS_Report classes

docs/en/changelogs/3.0.0.md

@@ -480,7 +480,19 @@ Note that its just necessary if SilverStripe is used in a language other than th
 		'legacy',
 		9 // priority lower than standard translator
 	);
-
+
+### Removed the need to register SS_Reports
+
+The SS_Report::register() method is deprecated. You no longer need to explicitly register reports. The CMS now
+automatically picks up and adds all Report classes to the list of reports in ReportAdmin. You can choose to exclude
+certain reports by using the SS_Report::add_excluded_reports() method.
+fe
+### Removed the ability use a SQLQuery object in a SS_Report
+
+You can no longer create reports that using the deprecated DataObject->buildSQL and DataObject->extendedSQL
+methods to build raw SQL queries. Instead please use the DataList::create function to create your query and modify it
+using the filter() function on the DataList object.
+
 ### Removed "auto-merging" of member records from `Member->onBeforeWrite()` [member-merging]
 
 Due to security reasons. Please use `DataObject->merge()` explicitly if this is desired behaviour.