Blacklist the .idea folder by adding the “.idea” folder to the .gitignore file in master, 
then commit this change.
In your branch, check this file out from master. 
git checkout master -- .gitignore
Remove the .idea folder from the git tree
git rm --cached -r .idea

and commit this change to your branch.

for reference : https://www.david-merrick.com/2017/08/04/how-to-remove-the-idea-folder-from-git/