diff --git a/.github/workflows/github-actions-demo.yml b/.github/workflows/github-actions-demo.yml
index 52df3db9..80408345 100644
--- a/.github/workflows/github-actions-demo.yml
+++ b/.github/workflows/github-actions-demo.yml
@@ -11,7 +11,7 @@ jobs:
         python_version: [3.11]
     runs-on: ${{ matrix.os }}
     env:
-      OS: : osx_arm64
+      OS: osx_arm64
       MINICONDA_INSTALLER_URL: https://repo.anaconda.com/miniconda/Miniconda3-latest-MacOSX-arm64.sh
       PROJECT_DIR: workdir/macos
       C_COMPILER: clang_osx-64