bump-formula-pr: add new command.
bump-formula-pr: add new command.

Add a new developer command (i.e. requires `HOMEBREW_DEVELOPER` set in
your environment) to bump the version of a formula and create a new pull
request with the new version.

Closes Homebrew/homebrew#49848.

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