diff --git a/.github/workflows/book-update.yml b/.github/workflows/book-update.yml
index ee0deeb..3f932c0 100644
--- a/.github/workflows/book-update.yml
+++ b/.github/workflows/book-update.yml
@@ -7,14 +7,14 @@ on:
 
 jobs:
   deploy:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
 
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1.1.13
         with:
-          mdbook-version: '0.4.7'
+          mdbook-version: "0.4.7"
           # mdbook-version: 'latest'
 
       - run: mdbook build