When donating the k8s-prometheus-adapter project to the CNCF, we could not
reach all the contributors to make them sign the CNCF CLA. As such, according
to the CNCF rules to donate a repository, we must add a NOTICE referencing
section 7 of the CLA with a list of developers who could not be reached.

`7. Should You wish to submit work that is not Your original creation, You may
submit it to the Foundation separately from any Contribution, identifying the
complete details of its source and of any license or other restriction
(including, but not limited to, related patents, trademarks, and license
agreements) of which you are personally aware, and conspicuously marking the
work as "Submitted on behalf of a third-party: [named here]".`

Submitted on behalf of a third-party: Andrew "thisisamurray" Murray
Submitted on behalf of a third-party: Duane "duane-ibm" D'Souza
Submitted on behalf of a third-party: John "john-delivuk" Delivuk
Submitted on behalf of a third-party: Richard "rrtaylor" Taylor
