Correct version 1.83 release date (#4355)

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 9ac85d4..698634b 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -99,7 +99,7 @@
 
 
 -----------------------------------------------------------------------
- VERSION 1.83 (Released 2011-05-24)
+ VERSION 1.83 (Released 2021-05-24)
 -----------------------------------------------------------------------
 
 Decorated log: https://github.com/ocornut/imgui/releases/tag/v1.83