[Docs Site] Rename /changelog-next/ to /changelog/, /changelog/ to /release-notes/

Author: KianNH

public/_redirects

@@ -4,6 +4,7 @@
 /dashboard-landing/ / 301
 /tutorials/ /search/?content_type%5B0%5D=Tutorial 301
 /sitemap.xml /sitemap-index.xml
+/changelog/index.xml /release-notes/index.xml 301
 
 # 1dot1_redirect
 /1.1.1.1/1.1.1.1-for-families/ /1.1.1.1/setup/ 301