git checkout dev
git pull --rebase --prune
git checkout -b feat/x # or fix/y

# coding time

# may commit several times
git commit -m ''

# make sure rebase from origin dev branch
git fetch
git rebase origin/dev
git push # maybe `-f` flag is required if you've pushed before rebase

# create Merge Request to dev branch

# code changes according MR review

# confirm to rebase again in case others merged before your MR
git fetch
git rebase origin/dev
git push