docs
https://docs.renovatebot.com/modules/platform/gitea/
https://docs.renovatebot.com/self-hosted-configuration/

create a personal access token on gitea and set it in RENOVATE_TOKEN

create a repo with this file on gitea .drone.yml

kind: pipeline
type: docker
name: renovate-bot
steps:
- name: run
  image: renovate/renovate
  commands:
  - renovate root/a2c
  environment:
    RENOVATE_TOKEN:
      from_secret: gitearenovate_token
    RENOVATE_USERNAME: root
    RENOVATE_PLATFORM: gitea
    RENOVATE_ENDPOINT: https://gitea.raphaelpiccolo.com/api/v1
    RENOVATE_GIT_URL: endpoint
    RENOVATE_GIT_AUTHOR: "Renovate Bot <renovate@example.com>"
    RENOVATE_AUTODISCOVER: true
    # RENOVATE_DRY_RUN: full

commit and push to trigger drone