[ci skip] Link the random extension RFCs in UPGRADING

see 4d8dd8d

Author: TimWolla

UPGRADING

@@ -112,6 +112,8 @@ PHP 8.2 UPGRADE NOTES
   . New extension that organizes and consolidates existing implementations
     related to random number generators. New, higher quality RNGs are available
     and scope issues are eliminated.
+    RFC: https://wiki.php.net/rfc/rng_extension
+    RFC: https://wiki.php.net/rfc/random_extension_improvement
 
 
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