Git@github.com: Permission denied (publickey). with Bitrise

I am using private git repo inside my swift package manager , when I integrate my app with Bitrise I am getting below error for private git repo

git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.
    Please make sure you have the correct access rights
    and the repository exists.skipping cache due to an error: Failed to clone repository "git@github.com: