Replace Greenkeeper with Dependabot about create-octokit-project.js

[gr2m]

Hmm turns out that Dependabot is sending PRs for all updates even with the versioning-strategy: "increase-if-necessary", but it only updates the lock file. I don't see how I'd be able to enable Dependabot with that setting, it's too much noise both for me and for (potential) contributors who watch the Octokit repositories :/

[gr2m]

I'll go ahead and migrate anyway, just to see how much noise it will be. Maybe it will help to make a case to the Dependabot team to introduce features that would lower the noise for library maintainers :)

I'll use this setting now

version: 2
updates:
  - package-ecosystem: "npm"
    directory: "/"
    schedule:
      interval: "daily"
    labels:
    - "maintenance"

[gr2m]

All done, getting ready for the flood. For reference, here is the script I used to create all the PRs:
https://github.com/gr2m/migrate-greenkeeper-to-dependabot-cli