README.md: Change Homebrew to Linuxbrew
README.md: Change Homebrew to Linuxbrew

hanxue/linuxbrew,maxim-belkin/brew,hanxue/linuxbrew,hanxue/linuxbrew,Linuxbrew/brew,rwhogg/brew,maxim-belkin/brew,maxim-belkin/brew,rwhogg/brew,Linuxbrew/brew,Linuxbrew/brew,rwhogg/brew,Linuxbrew/brew