Drop MediaWiki 1.47 from the release notes

MediaWiki 1.47 is still in development, so do not advertise support for it
yet (the underlying compatibility fix remains in place).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: JeroenDeDauw

README.md

@@ -83,7 +83,7 @@ Example: `https://commons.wikimedia.org/w/api.php`
 
 Released on June 12, 2026
 
-* Added support for MediaWiki 1.44, 1.45, 1.46, and 1.47
+* Added support for MediaWiki 1.44, 1.45, and 1.46
 * Translation updates
 
 ### Version 2.0.0