Bump rubocop from 1.8.1 to 1.20.0#24

dependabot[bot] wants to merge 1 commit intomasterula/heroku-buildpack-python:masterfrom

dependabot/bundler/rubocop-1.20.0ula/heroku-buildpack-python:dependabot/bundler/rubocop-1.20.0Copy head branch name to clipboard