Mark 4.0.2 as released (#23541)

Update changelog and emscripten-version.txt [ci skip]

Author: emscripten-bot

ChangeLog.md

@@ -18,8 +18,11 @@ to browse the changes between the tags.
 
 See docs/process.md for more on how version tagging works.
 
-4.0.2 (in development)
+4.0.3 (in development)
 ----------------------
+
+4.0.2 - 01/30/25
+----------------
 - The standard Wasm EH, enabled by `-sWASM_LEGACY_EXCEPTIONS=0`, now uses the
   LLVM backend implementation rather than the previously used Binaryen
   translator

emscripten-version.txt

@@ -1 +1 @@
-4.0.2-git
+4.0.3-git