Add https://adamws.github.io/kicad-plugin-template/repository.json to KiCad's repository list to use these packages:

{
    "packages": [
        {
            "$schema": "https://go.kicad.org/pcm/schemas/v1",
            "name": "Template",
            "description": "Template Plugin for KiCad",
            "description_full": "This is plugin template. It has no bigger purpose.\nVisit project homepage to learn more.",
            "identifier": "com.github.adamws.kicad-plugin-template",
            "type": "plugin",
            "author": {
                "name": "anonymous",
                "contact": {
                    "web": "https://example.com"
                }
            },
            "license": "MIT",
            "resources": {
                "Homepage": "https://github.com/adamws/kicad-plugin-template",
                "Bug Tracker": "https://github.com/adamws/kicad-plugin-template/issues"
            },
            "versions": [
                {
                    "version": "0.1.0",
                    "status": "development",
                    "kicad_version": "6.0",
                    "download_sha256": "7f344bc10d28a5bbe152e93599bed0cd1e7727809aadfe862dcab8be45362c44",
                    "download_size": 10247,
                    "install_size": 9295,
                    "download_url": "https://adamws.github.io/kicad-plugin-template/kicad_plugin_template-0.1.0.zip"
                }
            ]
        }
    ]
}