diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e5fb300..be5e0de 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -14,7 +14,9 @@ jobs:
     name: asdf plugin test
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os:
+          - ubuntu-latest
+          - macos-latest
     runs-on: ${{ matrix.os }}
     steps:
       - name: asdf_plugin_test