[google_sign_in]  fix merge error in CHANGELOG (#3153)

diff --git a/packages/google_sign_in/google_sign_in/CHANGELOG.md b/packages/google_sign_in/google_sign_in/CHANGELOG.md
index 756a599..7d3dc28 100644
--- a/packages/google_sign_in/google_sign_in/CHANGELOG.md
+++ b/packages/google_sign_in/google_sign_in/CHANGELOG.md
@@ -4,7 +4,7 @@
 
 ## 4.5.4
 
-* Update android compileSdkVersion to 29.
+* Keep handling deprecated Android v1 classes for backward compatibility.
 
 ## 4.5.3