update username and email gi t code example

Example 1: git change email

git config --global user.email "[email protected]"

Example 2: git change username email

# FOR ALL REPOS
## change username
git config --global user.name "John Doe"
## change email address
git config --global user.email "[email protected]"

# FOR CURRENT-DIRECTORY REPO ONLY
## change username
git config user.name "John Doe"
## change email address
git config user.email "[email protected]"