#642 Docker 이미지 레지스트리를 GHCR으로 이전

[kmc7468]

Summary

It closes #642

ECR에서 GHCR로 이전하고, Step에서 사용하는 액션들도 최신 버전으로 업데이트하였습니다.

Extra info

• #921 Docker 이미지 레지스트리를 GHCR으로 이전 taxi-front#922 와 함께 머지되어야 합니다.

[Copilot]

Pull Request Overview

This PR migrates Docker image registry from AWS ECR to GitHub Container Registry (GHCR) to address issue #642. The changes replace ECR-based workflows with GHCR equivalents and update GitHub Actions to their latest versions.

Key changes:

• Replace ECR workflows with GHCR-based Docker image building and pushing
• Update GitHub Actions to latest versions (v4, v5, v6)
• Simplify workflow structure by removing AWS-specific dependencies

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
.github/workflows/push_image_ghcr_dev.yml	New workflow for pushing dev images to GHCR on dev branch PR merges
.github/workflows/push_image_ghcr.yml	New workflow for pushing production images to GHCR on release publish
.github/workflows/push_image_ecr_dev.yml	Removed ECR dev workflow
.github/workflows/push_image_ecr.yml	Removed ECR production workflow

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