cmd/fetch: fix Rubocop warnings.
cmd/fetch: fix Rubocop warnings.

maxim-belkin/brew,Linuxbrew/brew,mgrimes/brew,Homebrew/brew,reitermarkus/brew,palxex/brew,pseudocody/brew,sjackman/homebrew,vitorgalvao/brew,Linuxbrew/brew,vitorgalvao/brew,zmwangx/brew,MikeMcQuaid/brew,bfontaine/brew,claui/brew,palxex/brew,pseudocody/brew,jmsundar/brew,DomT4/brew,alyssais/brew,Homebrew/brew,mahori/brew,sjackman/homebrew,Linuxbrew/brew,MikeMcQuaid/brew,reelsense/brew,konqui/brew,ilovezfs/brew,alyssais/brew,JCount/brew,toonetown/homebrew,toonetown/homebrew,rwhogg/brew,reelsense/brew,DomT4/brew,claui/brew,reitermarkus/brew,sjackman/homebrew,muellermartin/dist,tonyg/homebrew,toonetown/homebrew,maxim-belkin/brew,vitorgalvao/brew,mahori/brew,maxim-belkin/brew,EricFromCanada/brew,jmsundar/brew,mahori/brew,gregory-nisbet/brew,nandub/brew,MikeMcQuaid/brew,hanxue/linuxbrew,hanxue/linuxbrew,EricFromCanada/brew,nandub/brew,Linuxbrew/brew,muellermartin/dist,aw1621107/brew,mahori/brew,nandub/brew,ilovezfs/brew,pseudocody/brew,zmwangx/brew,claui/brew,palxex/brew,hanxue/linuxbrew,alyssais/brew,MikeMcQuaid/brew,JCount/brew,bfontaine/brew,reitermarkus/brew,rwhogg/brew,mgrimes/brew,reelsense/brew,DomT4/brew,JCount/brew,amar-laksh/brew_sudo,jmsundar/brew,konqui/brew,bfontaine/brew,vitorgalvao/brew,gregory-nisbet/brew,muellermartin/dist,claui/brew,DomT4/brew,reitermarkus/brew,JCount/brew,rwhogg/brew,sjackman/homebrew,gregory-nisbet/brew,amar-laksh/brew_sudo,konqui/brew,EricFromCanada/brew,amar-laksh/brew_sudo,mgrimes/brew,tonyg/homebrew,aw1621107/brew,tonyg/homebrew,ilovezfs/brew,Homebrew/brew,zmwangx/brew,Homebrew/brew,aw1621107/brew,EricFromCanada/brew,konqui/brew,nandub/brew