Deploy Error Github

I am very new to the scene and just trying to get my hands dirty and learn. I am getting this error when trying to deploy from github using forge deployment:

Your local changes to the following files would be overwritten by merge: vendor/composer/autoload_classmap.php Please, commit your changes or stash them before you can merge. Aborting

I have googled around but not found anything yet. If anyone knows whats causing this issue I would greatly appreciate it!