🐛 Fix checking commit message

Author: jiro4989

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     if: "! contains(github.event.head_commit.message, '[skip ci]')"
     steps:
-      - run: echo ${{ github.event.head_commit.message }}
+      - run: echo "${{ github.event.head_commit.message }}"
 
   build:
     runs-on: ubuntu-latest