Project's contribution based on changes made in composer vendor folder

gistfile1.txt

# Go into the directory of the vendor package that you changed
cd vendor/<owner>/<package>

# Create a new git repository
git init

# Create a new 'main' branch
git checkout -b main

# Commit all your changes
git add .
git commit -m "Your comment here"

# Add the git remote, which contains the source code your fork from original package project
git remote add origin git@github.com:<repo>.git

# Create the new branch 'develop' based on remote git
git fetch origin develop:develop

# List all tags and find one that corresponds to version of installed vendor package
git tag -l

# Create the new branch 'issue-xxx' based on specified tag
git checkout -b issue-xxx tags/YYY

# Execute reverse git diff and apply all your changes
git diff -R main | git apply --whitespace=fix

# Commit all your changes again
git add .
git commit -m "Your comment here"

# Push your branch 'issue-xxx' to remote git
git push -u origin issue-xxx

# Now you can create a Pull Request if you want