diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f88c2b1..c1d3ab5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -22,7 +22,7 @@ jobs:
       - name: tests
         run: cd build && ctest --output-on-failure
   ubuntu-20-04-build-gcc:
-    runs-on: ubuntu-20-04
+    runs-on: ubuntu-20.04
     steps:
       - name: Checkout repository code
         uses: actions/checkout@v2