Fix failing workflow runs on Mac for 1.13 and 1.15

[williammartin]

Description

I have no idea why these are failing but we should make sure to get our build green.

https://github.com/cli/oauth/actions/runs/11253277416/job/31288198916

[williammartin]

I think it's because Go wasn't built for ARM until 1.16 and GitHub MacOS runners are now ARM by default.

golang/go#44115

https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources

[williammartin]

Unfortunately just dropping back to the x86 runner fixes 1.15 but causes another issue for 1.13: https://github.com/cli/oauth/actions/runs/11253623853/job/31289596969#step:4:12

I'm not really sure there is any good reason to keep testing on such old versions. Technically our go.mod says the latest language version required is 1.13, and that's true but I also don't really feel the need to spend too much time thinking about versions that are long ago unsupported. If someone has an issue on an older version they can create an issue here and we can think about it.