You are submitting a new apk to Google; from Google’s side, they do not care what you change (as long as it won’t harm anyone). The play store knows that you uploaded a new apk which is different than the current one installed so it is going to download the new apk. An apk is one file so there is no way to pick which parts to update. It sounds like you want to use something like Ionic Deploy.
Thanks alot for reply ! but there are many apps on playstore which update partially i mean the new changes and not full apk again so i thought there is way to do it. checking ionic deploy