Add missing PR link to Changelog

Author: IshaanDesai

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## v0.4.1
 
-- remove std::sqrt from constexpr - failed on Clang
+- remove std::sqrt from constexpr - failed on Clang https://github.com/DataAnalyticsEngineering/FANS/pull/64
 
 ## v0.4.0