fix(cd): include changelog in GitHub releases and update date placeholder

- Add Changelog section to release body with generated commit history
- Replace placeholder date "2026-XX-XX" with "TBD" in CHANGELOG.md
- Changelog now displays in GitHub releases between Docker images and package link

Author: nanotaboada

.github/workflows/python-cd.yml

@@ -156,6 +156,10 @@ jobs:
             docker pull ghcr.io/${{ env.PACKAGE_NAME }}:latest
             ```
 
+            ## Changelog
+
+            ${{ steps.changelog.outputs.changelog }}
+
             ---
 
             📦 **Package:** [ghcr.io/${{ env.PACKAGE_NAME }}](https://github.com/${{ github.repository }}/pkgs/container/python-samples-fastapi-restful)

CHANGELOG.md

@@ -52,7 +52,7 @@ This project uses famous football coaches as release codenames, following an A-Z
 
 ---
 
-## [1.0.0 - Ancelotti] - 2026-XX-XX
+## [1.0.0 - Ancelotti] - TBD
 
 ### Added