diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3be30deb..5ae57ed4 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,9 +6,13 @@ on:
   schedule:
     - cron: '37 22 * * *'
 
+defaults:
+  run:
+    shell: bash
+
 jobs:
   build:
-    runs-on: ${{ matrix.os }}
+    runs-on: ${{ matrix }}
     strategy:
       matrix:
         os: [ubuntu-16.04, ubuntu-18.04, ubuntu-20.04, macos-10.15, windows-2019]