diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 82e923f..3b720e5 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,7 +8,7 @@ jobs:
     strategy:
       max-parallel: 5
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ['3.6', '3.7', '3.8', '3.9']
 
     steps:
     - uses: actions/checkout@v2