ci: do not run PR tests on macOS

Running on main branch only is enough,
it is unlikely that macOS does not work when Linux does.

Author: link2xt

.github/workflows/ci.yml

@@ -116,6 +116,12 @@ jobs:
           # Minimum Supported Rust Version
           - os: ubuntu-latest
             rust: minimum
+
+        # Do not run macOS on PRs, it is slow.
+        # macOS CI will run on main branch once PR is merged.
+        exclude:
+          - os: github.event_name == 'pull_request' && 'macos-latest' || ''
+
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
@@ -345,6 +351,11 @@ jobs:
           - os: ubuntu-latest
             python: "3.10"
 
+        # Do not run macOS on PRs, it is slow.
+        # macOS CI will run on main branch once PR is merged.
+        exclude:
+          - os: github.event_name == 'pull_request' && 'macos-latest' || ''
+
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps: