Squashing Git Commits
The easy and flexible way
This method avoids merge conflicts if you have periodically pulled master into your branch. It also gives you the opportunity to squash into more than 1 commit, or to re-arrange your code into completely different commits (e.g. if you ended up working on three different features but the commits were not consecutive).
Note: You cannot use this method if you intend to open a pull request to merge your feature branch. This method requires committing directly to master.
Switch to the master branch and make sure you are up to date: