diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c877a47..3bb2e15 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -4,11 +4,10 @@ on:
   schedule: [{ cron: "0 21 * * sun" }] # Every Monday at 6am Asia/Tokyo UTC+9
 jobs:
   main:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - run: sudo apt-get install -y qemu-user-static
       - run: docker login docker.pkg.github.com -u "${GITHUB_ACTOR}" -p "${{ github.token }}"
-      - uses: mxschmitt/action-tmate@v2
       - run: bin/build
       - run: docker-compose push