diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 6252823..ebb6058 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         sys:
-         - { os: windows-latest, shell: 'msys2 {0}' }
+          - { os: windows-latest, shell: 'msys2 {0}' }
           - { os: ubuntu-latest,  shell: bash  }
           - { os: macos-latest,   shell: bash  }
     defaults: