Ignore RuboCop changes in Git Blame

Have you ever run git blame, looked at the commit for a line, and seen some big refactoring or formatting commit? It’s so frustrating not to be able to find the useful context on changes when this happens. When adding StandardRB or RuboCop, or when making changes to your .rubocop.yml configuration, you’ll probably end up with a large commit like this that doesn’t include valuable context when spelunking history.