Comment by TekMol
I am using Git submodules for dependencies. My approach to a situation like this:
1: Clone gh.com/someone/LibBar to gh.com/me/LibBar
2: Fix the bug
3: Send pull request to someone
5: git submodule set-url lib/LibBar https://gh.com/me/LibBar.git
git submodule sync lib/LibBar
git submodule update --init --remote --recursive lib/LibBar
cd lib/LibBar/; git checkout main; cd ../..
git add .; git commit -m "Use my own version of lib/LibBar"
And keep using my fork until upstream accepted my pull request. Then I switch the url of the dependency back.