Update DCO Checker script link

[matthewlow-dwa]

Updates the DCO Checker script link on the Contribution Guidelines page. The old repo link has been deprecated in favor of the newer repository.

[jfpanisset]

@jmertic Should this script / repo be "vendored" into the ASWF Org repo?

[jfpanisset]

LGTM, perhaps consider if ASWF org should perhaps have its own fork of that repo?

[jmertic]

I don't see a need to vendor/fork this repo @jfpanisset - are you seeing a use case for doing that?

[jfpanisset]

Of course we all know you, but as a general rule, isn't it preferable for project to avoid dependencies in their CI to repos from individual GitHub accounts?

This particular PR doesn't change this situation, it just fixes a broken link, but more generally perhaps the DCO tooling should live under the LF GitHub org?

[jmertic]

@jfpanisset I would say in general, forks are a anti-pattern. Pinning dependencies is a good practice, but here this is just a tool to use and not a dependency per se.

As for the tooling under the LF, it's not really maintained by the LF officially, just me right now. But maybe that is something to review for us internally.