Build and Publish amd64 binaries for MacOSX

[moshloop]

It appears that amd64 binaries for macosx were published up until v14.1 but then stopped from v14.2 and onwards.

I think that dropping support for Intel based Macs is very reasonable for an OSS project todo, however I have 2 concerns:

1. It is a backwards incompatible change and should at least be mentioned in the release notes AND/OR wait for major release bump
2. There are no statically compiled binaries for MacOS, so if even if you use the arm version and you happen to have a amd64 postgres installed (via brew or otherwise) postgrest will fail to run due to library arch incompatibility.

[steve-chavez]

This was done on eb00c19.

@wolfgangwalther Maybe we can reintroduce this? According to https://github.blog/changelog/2025-09-19-github-actions-macos-13-runner-image-is-closing-down/ macos-15-intel will be available until 2027.