renovate.json5

{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "extends": [
    "config:recommended"
  ],
  "customManagers": [
    {
      "customType": "regex",
      "fileMatch": [
        "Dockerfile"
      ],
      "matchStrings": [
        "CADDY_VERSION=(?<currentValue>v\\d+\\.\\d+\\.\\d+)"
      ],
      "datasourceTemplate": "go",
      "packageNameTemplate": "github.com/caddyserver/caddy/v2",
      "versioningTemplate": "semver"
    },
    {
      "customType": "regex",
      "fileMatch": [
        "Dockerfile"
      ],
      "matchStrings": [
        "(?<packageName>github\\.com/[^\\s@]+)@(?<currentValue>v?\\d+\\.\\d+\\.\\d+(\\-[0-9]+\\-[a-z0-9]+)?)"
      ],
      "datasourceTemplate": "go",
      "packageNameTemplate": "{{packageName}}",
      "versioningTemplate": "semver"
    }
  ]
}