Provide implementation guidance for DCO/CLA

[tobie]

In #618 we agreed that it would be useful to provide guidance for DCO/CLA implementation and day to day use for both project maintainers and contributors.

For Project maintainers

Project maintainers need guidance to:

• Set up DCO/CLA infra.
• Document DCO/CLA requirements for contributors.
• Handle common issues with DCO/CLA, e.g. for DCO:
  • What happens when there are multiple authors?
  • What happens when commits are squashed?
  • Can I sign off for someone else when I merge a commit?
  • What if I'm batch-merging commits made with GitHub's "insert a suggestion" feature?
  • Is a Sign-off-by in the body of the pull request good enough?

Contributors

• Understand what they have to do to contribute IP.
• Understand when they need employer agreement to do so.
• Solve common problems they might bump into.

[christian-bromann]

I am happy to be the guinea pig and help getting it set up in WebdriverIO.

[mmarchini]

Set up DCO/CLA infra.

Do we have an existing suggestion for setting up DCO/CLA infrastructure? With GitHub newly introduced pull_request_target event for Actions, it's likely that we can implement it solely as an Action.

[MylesBorins]

@brianwarner has experimented with some implementations of this

[jorydotcom]

Reporting back on this issue - @brianwarner has been working with the folks at the ProBot DCO project to incorporate some upstream changes that work for our use case. These are incoming!

[bnb]

for context from today's meeting: there was a request from the probot/dco maintainers to have someone maintain the code that @brianwarner PR'ed in. IMO this is a reasonable request. I've asked if they'd be willing to add CODEOWNERS for these sections of code, and if so that makes it simpler to fence off the commitment. Ideally, we'd find someone from the CPC or member projects who'd be willing to take that responsibility.

[rginn]

Today we learned that the Probot DCO will be shut down in 4 weeks if no one takes on ownership. dcoapp/app#162. I will connect the dots with those potentially interested in supporting this from the Linux Foundation.