Add CHANGELOG entry

CHANGELOG.md

@@ -4,11 +4,17 @@
 
 💥 Breaking changes:
 
+- Update accordion to use new WCAG 2.1 compliant focus style
+
+  To migrate: [TODO add migration instructions before we ship v3.0.0]
+
+  ([PR #1324](https://github.com/alphagov/govuk-frontend/pull/1324))
+
 - Update form inputs to use new WCAG 2.1 compliant focus style
 
   To migrate: [TODO add migration instructions before we ship v3.0.0]
 
-  ([PR #1312](https://github.com/alphagov/govuk-frontend/pull/13))
+  ([PR #1312](https://github.com/alphagov/govuk-frontend/pull/1312))
 
 - Update links (and things that look like links) to use the new focus style
 
@@ -124,6 +130,10 @@
 
 🔧 Fixes:
 
+- Update accordion focus styles to remove firefox outlines
+
+  ([PR #1324](https://github.com/alphagov/govuk-frontend/pull/1324))
+
 - Rename `$govuk-border-width-mobile` to `$govuk-border-width-narrow`
 
   This better reflects how the variable is used.