Some Basic Program in Various Languages.
Add the remote, call it "upstream":
git remote add upstream https://github.com/vinayskywalker/Hactoberfest2020
Fetch all the branches of that remote into remote-tracking branches, such as upstream/main:
git fetch upstream
Make sure that you're on your main branch:
git checkout main
Rewrite your main branch so that any commits of yours that aren't already in upstream/main are replayed on top of that other branch:
git rebase upstream/main