Update CHANGELOG.md

CHANGELOG.md

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-  cSpell:ignore docsy
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 # Changelog
@@ -33,6 +33,12 @@ notes][0.5.0]. **BREAKING CHANGES** are documented below.
   upgrade. You might notice other width changes of elements using FA icons and
   the FA font.
 
+**Other changes**:
+
+- By default, Docsy now uses the [gtag.js][] analytics library for all site
+  tags. For details, see [Adding Analytics > Setup][].
+
+[Adding Analytics > Setup]: https://www.docsy.dev/docs/adding-content/feedback/#setup
 [v4.6.2 release notes]: https://github.com/twbs/bootstrap/releases/tag/v4.6.2
 [docsy as an npm package]:
   https://www.docsy.dev/docs/get-started/other-options/#option-3-docsy-as-an-npm-package