Update cherry-pick pr script to use mergebase (#32031)
Update cherry-pick pr script to use mergebase (#32031)


kpreisser/TypeScript,weswigham/TypeScript,minestarks/TypeScript,alexeagle/TypeScript,kitsonk/TypeScript,kpreisser/TypeScript,nojvek/TypeScript,kpreisser/TypeScript,microsoft/TypeScript,alexeagle/TypeScript,kitsonk/TypeScript,microsoft/TypeScript,minestarks/TypeScript,RyanCavanaugh/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,weswigham/TypeScript,RyanCavanaugh/TypeScript,RyanCavanaugh/TypeScript,kitsonk/TypeScript,SaschaNaz/TypeScript,minestarks/TypeScript,weswigham/TypeScript,nojvek/TypeScript,alexeagle/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,microsoft/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,nojvek/TypeScript,nojvek/TypeScript