covfefe: housekeeping

[dnwe]

I was checking out covfefe recently and thought I may as well offer up the local changes I did whilst setting it up. Not sure if you're accepting PRs, but feel free to close the PR without comment if you're not.

---

• covfefe: add minimal README.md and creds example

• covfefe: refresh dependencies

  General version bump for everything, but more notably:

  • go mod edit -go=1.17
  • go mod tidy -compat=1.17
  • github.com/dghubble/gologin => /v2
  • github.com/v2pro/plz/gls => github.com/modern-go/gls