Add missing entries for abt

Author: rlazo

firebase-abt/CHANGELOG.md

@@ -1,2 +1,34 @@
 # Unreleased
 
+# 21.0.2
+* [changed] Updated dependency of `play-services-basement` to its latest
+  version (v18.1.0).
+
+# 21.0.1
+* [changed] Updated dependencies of `play-services-basement`,
+  `play-services-base`, and `play-services-tasks` to their latest versions
+  (v18.0.0, v18.0.1, and v18.0.1, respectively). For more information, see the
+  [note](#basement18-0-0_base18-0-1_tasks18-0-1) at the top of this release
+  entry.
+
+# 21.0.0
+* [changed] Internal infrastructure improvements.
+* [changed] Internal changes to support dynamic feature modules.
+
+# 20.0.0
+* [removed] Removed the protocol buffer dependency and moved relevant protocol
+  buffer definitions to [inappmessaging_longer]. If you use [ab_testing]
+  with [inappmessaging], you'll need to update to
+  [inappmessaging] v19.1.2 or later.
+
+# 19.0.1
+- [changed] Internal changes to ensure functionality alignment with other SDK releases.
+
+# 17.1.1
+* [changed] Updated API to support the latest [remote_config] update.
+
+* [changed] Updated minSdkVersion to API level 16.
+
+# 17.1.0
+* [changed] Updated API to support the latest [remote_config] update.
+