fix: create an image with the tag latest

Author: yutaro-sakamoto

.github/workflows/ci.yml

@@ -24,6 +24,10 @@ jobs:
           docker build -t opensourcecobol/opensourcecobol4j:"$version_string_prefix"-debug . \
           --build-arg opensource_COBOL_4J_version="$opensource_COBOL_4J_version" \
           --build-arg Open_COBOL_ESQL_4J_version="$Open_COBOL_ESQL_4J_version"
+      
+      - name: Copy Docker image
+        run: |
+          docker tag opensourcecobol/opensourcecobol4j:"$version_string_prefix"-debug opensourcecobol/opensourcecobol4j:"$version_string_prefix"-debug-latest
 
       - name: Login to Docker Hub
         if: github.ref == 'refs/heads/y-sakamoto/auto-deploy' && github.event_name == 'push'