Clarify the pull request review guidance for company diversity

As discussed at the governance/community meeting on 25/10, we clarify
the guidance on company diveristy for reviews. This update upholds that
company diversity is an important recommendation that should be observed
when appropriate, not a policy that is applied to all pull requests. For
example, if the changes are minor or they have been discussed in a TEP.

This is to ensure that we don't further slow down reviews in the project
when we have already gathered diverse input on the change in a design, or
the change is minor and reversible.

process/README.md

@@ -129,9 +129,12 @@ The configuration for this automation is in
 _More on the Prow process in general
 [is available in the k8s docs](https://github.com/kubernetes/community/blob/master/contributors/guide/owners.md#the-code-review-process)._
 
-The Tekton community promotes company diversity as a best practice for pull request.
-This means that, where possible, one of the reviewers of a pull request and the author
-should be affiliated to different organizations.
+The Tekton community promotes company diversity as a best practice for pull requests
+to encourage a wide range of perspectives and feedback. This means that, where appropriate
+and possible, one of the reviewers of a pull request and the author should be affiliated to
+different organizations. If the changes are minor and reversible or have been already been
+discussed in a [TEP] with input and approval from different organizations, the pull request
+can be approved by the same organization.
 
 This best practice may not be applicable by all Tekton projects, please check the
 guidelines on a project specific details for more details.
@@ -227,3 +230,6 @@ Postmortems should cover:
 - How can we detect similar incidents in the future more quickly?
 - How can we reduce the impact of similar incidents?
 - How can we prevent similar incidents from happening at all?
+
+
+[TEP]: tep-process.md