chore: add changelog to cloud-rad (#1082)

Author: eaball35

synthtool/gcp/templates/java_library/.kokoro/release/publish_javadoc11.sh

@@ -42,6 +42,8 @@ mvn clean site -B -q -P docFX
 
 # copy README to docfx-yml dir and rename index.md
 cp README.md target/docfx-yml/index.md
+# copy CHANGELOG to docfx-yml dir and rename history.md
+cp CHANGELOG.md target/docfx-yml/history.md
 
 pushd target/docfx-yml