travis.yml: bump ulimit to 1024
travis.yml: bump ulimit to 1024

Closes Homebrew/homebrew#43635.

Signed-off-by: Mike McQuaid <a17fed27eaa842282862ff7c1b9c8395a26ac320@mikemcquaid.com>

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