git filter-branch --commit-filter.sh

git log --summary --pretty=full | less
git filter-branch --commit-filter '
  if [ "$GIT_AUTHOR_EMAIL" = "oldname@users.noreply.github.com" ];
  then
    GIT_AUTHOR_NAME="newname";
    GIT_AUTHOR_EMAIL="newname@users.noreply.github.com";
    GIT_COMMITTER_NAME="newname";
    GIT_COMMITTER_EMAIL="newname@users.noreply.github.com";
    git commit-tree "$@";
  else
    git commit-tree "$@";
  fi' HEAD
git reflog expire --expire=now --all
git gc --aggressive --prune=now