diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index f608c2a..c9c5e7b 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -8,7 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: [3.8]
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     environment: aws
 
     steps: