message: build: add mainBranchName to github configuration
  Update the ng-dev config for Github to include the main branch name.
  PR Close
diff: @@ -4,8 +4,8 @@ import {GithubConfig} from '@angular/dev-infra-private/ng-dev/utils/config';
  * Github configuration for the `ng-dev` command. This repository is used as
  * remote for the merge script and other utilities like `ng-dev pr rebase`.
  */
  -
  export const github: GithubConfig = {
  owner: 'angular',
  - name: 'angular'
  + name: 'angular',
  + mainBranchName: 'master',
  };
  