docker.test.yml: Add --keep-old to brew test-bot
docker.test.yml: Add --keep-old to brew test-bot

gnubila-france/linuxbrew,Linuxbrew/linuxbrew,SuperNEMO-DBD/cadfaelbrew,Angeldude/linuxbrew,sjackman/linuxbrew,sjackman/linuxbrew,Linuxbrew/linuxbrew,SuperNEMO-DBD/cadfaelbrew,gnubila-france/linuxbrew,sjackman/linuxbrew,reelsense/linuxbrew,reelsense/linuxbrew,saketkc/linuxbrew,saketkc/linuxbrew,Homebrew/linuxbrew,sjackman/linuxbrew,saketkc/linuxbrew,saketkc/linuxbrew,reelsense/linuxbrew,Angeldude/linuxbrew,Angeldude/linuxbrew,Homebrew/linuxbrew,Homebrew/linuxbrew,Angeldude/linuxbrew,SuperNEMO-DBD/cadfaelbrew,gnubila-france/linuxbrew,gnubila-france/linuxbrew,Homebrew/linuxbrew,Linuxbrew/linuxbrew,Linuxbrew/linuxbrew,SuperNEMO-DBD/cadfaelbrew,reelsense/linuxbrew