Changing author info without massacring upstream

prepare-for-github.sh

#!/bin/sh
# vim: set et sw=4 ts=4 ff=unix ft=sh :

git filter-branch --env-filter '
OLD_EMAIL="private@email.com"
CORRECT_NAME="Your Name"
CORRECT_EMAIL="yourname@users.noreply.github.com"
if [ "$GIT_COMMITTER_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_COMMITTER_NAME="$CORRECT_NAME"
    export GIT_COMMITTER_EMAIL="$CORRECT_EMAIL"
fi
if [ "$GIT_AUTHOR_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_AUTHOR_NAME="$CORRECT_NAME"
    export GIT_AUTHOR_EMAIL="$CORRECT_EMAIL"
fi
' --tag-name-filter cat -- --branches --tags @{u}..HEAD