Introduce multi stage builds

[yutaro-sakamoto]

This pull request introduces significant updates to the Dockerfiles for building and running the opensource COBOL 4J development environment, including the addition of a multi-stage build process and the upgrade of dependencies. The README.md file has also been updated to reflect the new version of Open Source COBOL 4J.

Dockerfile Improvements:

• Multi-Stage Build Process: Introduced a two-stage build process in Dockerfile and utf8.Dockerfile to separate the build and runtime environments, reducing the size of the final image. [1] [2]
• Upgrade to Open Source COBOL 4J v1.1.9: Updated the build process to use version 1.1.9 of opensource COBOL 4J, replacing the previous v1.1.7. [1] [2]

[Copilot]

Pull Request Overview

This pull request introduces a multi-stage build process for the Open Source COBOL 4J development environment while upgrading dependencies to version v1.1.9. The key changes include:

• Implementing separate builder and runtime stages in both Dockerfile and utf8.Dockerfile.
• Upgrading Open Source COBOL 4J from v1.1.7 to v1.1.9.
• Updating the README.md to reflect the new version and image changes.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
utf8.Dockerfile	Introduces multi-stage build and builds COBOL 4J with UTF-8 support; note duplicate CMD instruction.
Dockerfile	Implements multi-stage build with separate installation of COBOL 4J and Open COBOL ESQL 4J; update includes removal of previous tarball cleanup.
README.md	Updates version information to reflect the upgrade to v1.1.9.