Remove deprecated .govuk-tag--inactive class

Class govuk-tag--inactive was replaced by govuk-tag--grey and deprecated
in PR #1711.

This commit removes the class completely. You should replace any uses of
this class with `.govuk-tag--grey`.

CHANGELOG.md

@@ -57,6 +57,14 @@ If you’re calling `iff` from your own Sass, you should use [Sass's native `if`
 
 This change was introduced in [pull request #2409: Remove deprecated `iff` Sass function](https://github.com/alphagov/govuk-frontend/pull/2409).
 
+#### Remove deprecated `.govuk-tag--inactive` class
+
+We've removed the `.govuk-tag--inactive` class which we deprecated in [GOV.UK Frontend v3.6.0](https://github.com/alphagov/govuk-frontend/releases/tag/v3.6.0).
+
+Replace any use of this class with the `.govuk-tag--grey` class.
+
+This change was introduced in pull request #: Remove deprecated `.govuk-tag--inactive class`.
+
 ### Fixes
 
 We’ve made fixes to GOV.UK Frontend in the following pull requests:

src/govuk/components/tag/_index.scss

@@ -34,11 +34,6 @@
     }
   }
 
-  // Deprecated. We'll remove this class in a future release. Use `.govuk-tag--grey` instead.
-  .govuk-tag--inactive {
-    background-color: govuk-colour("dark-grey", $legacy: "grey-1");
-  }
-
   .govuk-tag--grey {
     color: govuk-shade(govuk-colour("dark-grey", $legacy: "grey-1"), 30);
     background: govuk-tint(govuk-colour("dark-grey", $legacy: "grey-1"), 90);