This release deprecates @backstage/plugin-todo and @backstage/plugin-todo-backend has they have now been moved to the @backstage-community/* namespace over in the community-plugins repository.
You should be able to do yarn backstage-cli versions:bump if you're already on v1.26.0+ of Backstage.
Otherwise, you can do do yarn backstage-cli versions:bump followed by yarn backstage-cli versions:migrate to switch over to the new packages, if you're on versions <v1.26.0