Adds 8213 rn (quay#1367)

Co-authored-by: Steven Smith <[email protected]>

Author: stevsmit

modules/rn_3_15_0.adoc

@@ -169,6 +169,17 @@ The following issues were fixed with {productname} 3.15:
 
 * link:https://issues.redhat.com/browse/PROJQUAY-6862[*PROJQUAY-6862*]. Previously, when {productname} was deployed with Google Cloud Storage (GCS) as its object storage backend, pushing layers greater than 4 GiB would fail and return a `413` error. This error occurred because {productname}'s library, boto, does not support multipart uploads to GCS. This issue has been resolved, and users can now push layers greater than 4 GiB to their registry without interruption.
 
+* link:https://issues.redhat.com/browse/PROJQUAY-8123[*PROJQUAY-8123*]. Previously, if a {productname} administrator set up their deployment on a virtual machine (VM) and the administrator created the `config.yaml` file manually, there was a possibility that the `TESTING` flag was not included in the configuration. Including the `TESTING: true` field in the `config.yaml` file disables some features, such as sending emails. This is useful for developers who are testing {productname} and do not want to accidentally send out notifications or other alerts to users. When this field is not set, {productname} operates normally. 
++
+With this update, a warning is printed upon startup, notifying the {productname} administrator that the `TESTING` property is either missing from the `config.yaml` file entirely, or that it is set to `true`. This alert is intended to help guide administrators towards intentional configurations for their deployment.
+
+* link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
+* link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
+* link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
+* link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
+* link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
+* link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
+
 * link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
 * link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].
 * link:https://issues.redhat.com/browse/PROJQUAY-[*PROJQUAY-*].