diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 9293f55..25cc048 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -27,7 +27,7 @@ jobs:
       matrix:
         # test all Rust versions on Ubuntu
         rust: [stable, 1.57.0]
-        os: [ubuntu-latest, m]
+        os: [ubuntu-latest]
         # test stable Rust on Windows and MacOS as well
         include:
           - rust: stable