ci: bump lite interpreter to macOS 12 (#81882)
Don't know if there's a reason for this to be on 10.15 but Github is
going to eventually deprecate these runners so better to just move this
up rather than suffer the wrath of using a deprecated runner
<img width="1198" alt="Screen Shot 2022-07-21 at 3 23 58 PM" src="https://user-images.githubusercontent.com/1700823/180238298-54d02954-3e7c-4e28-852c-c99203bea322.png">
Reference: https://github.com/pytorch/pytorch/actions/runs/2712176357
Signed-off-by: Eli Uriegas <eliuriegas@fb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81882
Approved by: https://github.com/atalman, https://github.com/janeyx99
