This git command make several commits group into 1 commit.
git rebase -i HEAD~n
You can remove n commits into 1 single or m other commits.
After typing the above command, hit enter.
Put pick in front of commits which you want to remain.
Put squash in front of commits which you want to break.
Save the result.
https://stackoverflow.com/questions/12522565/how-can-i-combine-two-commits-into-one-commit/42844122
https://medium.com/@igor_marques/combining-two-commits-84281f470ee8