chore: test on linux only

Author: dcarp

.github/workflows/main.yml

@@ -10,11 +10,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os: [ubuntu-latest]
         dc: [dmd-latest, ldc-latest]
-        exclude:
-          - os: macos-latest
-            dc: dmd-latest # dmd is not available on macOS ARM runners
     runs-on: ${{ matrix.os }}
     timeout-minutes: 30
     steps: