diff --git a/.github/workflows/unit.yml b/.github/workflows/unit.yml
index 60583e9d..f346fccc 100644
--- a/.github/workflows/unit.yml
+++ b/.github/workflows/unit.yml
@@ -12,7 +12,7 @@ on:
 jobs:
   coverage-test:
     name: Coverage
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - name: Set up ruby 3.1