Add GHA status for mirroring repository

Author: igorpecovnik

README.md

@@ -21,3 +21,4 @@ It prepares several data exchange files.
 | Update download JSON index|<a href=https://github.com/armbian/armbian.github.io/actions/workflows/generate-web-index.yml><img alt="GitHub Workflow Status" src="https://img.shields.io/github/actions/workflow/status/armbian/armbian.github.io/generate-web-index.yml?logo=githubactions&label=Status&style=for-the-badge&branch=main"></a>|
 | Pull excerpts from Armbian Jira|<a href=https://github.com/armbian/armbian.github.io/actions/workflows/generate-jira-excerpt.yml><img alt="GitHub Workflow Status" src="https://img.shields.io/github/actions/workflow/status/armbian/armbian.github.io/generate-jira-excerpt.yml?logo=githubactions&label=Status&style=for-the-badge&branch=main"></a>|
 | USB wireless performance testig |<a href=https://github.com/armbian/armbian.github.io/actions/workflows/usb-wireless-autotest.yml><img alt="GitHub Workflow Status" src="https://img.shields.io/github/actions/workflow/status/armbian/armbian.github.io/usb-wireless-autotest.yml?logo=githubactions&label=Status&style=for-the-badge&branch=main"></a>|
+| Mirror repository artifacts to our CDN |<a href=https://github.com/armbian/armbian.github.io/actions/workflows/mirror.yml><img alt="GitHub Workflow Status" src="https://img.shields.io/github/actions/workflow/status/armbian/armbian.github.io/mirror.yml?logo=githubactions&label=Status&style=for-the-badge&branch=main"></a>|