Create .gitpod.yml

[gitolicious]

Description:

Gitpod configuration

Pull request in esphome with python changes (if applicable): esphome/esphome#508 Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#225

Checklist:

• [x] The code change is tested and works locally.
• [x] The code change follows the standards

If user exposed functionality or configuration variables are added/changed:

• [x] Documentation added/updated in esphome-docs.