Update changelog.txt

Author: lucasborin

changelog.txt

@@ -12,7 +12,7 @@ Upgrade Note
 ------------------
 Whenever you upgrade code pal for ABAP, it is highly recommended to execute the Y_CI_CHECK_REGISTRATION report to activate/reactivate the Checks (SE38 transaction) and regenerate the respective Code Inspector Variant (SCI transaction)
 
-2021-05-XX v.1.15.0
+2021-08-12 v.1.15.0
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 + Make Messages Easy to Find (#419)
 + Make Messages Translatable (#420)