remove PR description ref

Author: DaedalusG

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,13 +2,6 @@
 
 ### Checklist
 
-<!--
-  Kubernetes and Docker Compose MUST be kept in sync. You should not merge a change here
-  without a corresponding change in the other repository, unless it truly is specific to
-  this repository. If uneeded, add link or explanation of why it is not needed here.
--->
-* [ ] Sister [deploy-sourcegraph](https://github.com/sourcegraph/deploy-sourcegraph) change:
-* [ ] Sister [customer-replica](https://github.com/sourcegraph/deploy-sourcegraph-docker-customer-replica-1) change (if necessary, for any changes affecting pure-docker or configuration):
 * [ ] All images have a valid tag and SHA256 sum
 ### Test plan