[ci] switch from macos-14 to macos-15 runners #7476

Merged
jameslamb opened 4:42pm on September 29, 2026 wanted to merge 33 Δ into microsoft/lightgbm main from
ci/fix-macos-14-jobs

Pull Request #7476 commits

The 33.02 Diff Delta for this pull request is held by the squashed merge commit.