fix: specify initial branch name to suppress Git hint

[stevapple]

  hint: Using 'master' as the name for the initial branch. This default branch name
  hint: is subject to change. To configure the initial branch name to use in all
  hint: of your new repositories, which will suppress this warning, call:
  hint: 
  hint: 	git config --global init.defaultBranch <name>
  hint: 
  hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
  hint: 'development'. The just-created branch can be renamed via this command:
  hint: 
  hint: 	git branch -m <name>
  Initialized empty Git repository in /Users/runner/work/_actions/SwiftyLab/setup-swift/v1.4.1/.git/

[soumyamahunt]

Thanks @stevapple, all the checks are passing. Do you like to make any other changes here or this can be merged?

[stevapple]

I think this is a simple and complete fix✅

[soumyamahunt]

LGTM