Update ci.yml

Author: dlwls423

.github/workflows/ci.yml

@@ -31,6 +31,5 @@ jobs:
         run: ./gradlew clean build --stacktrace
         shell: bash
 
-      - uses: actions/checkout@v4
       - name: Build the Docker image
         run: docker build . --file Dockerfile --tag kodaero:$(date +%s)