Update pull_request_template.md (#3505)

Include additional guidance on how to test changes made to dbt models.

.github/pull_request_template.md

@@ -15,6 +15,8 @@ Resolves #\[issue\]
 
 _Include commands/logs/screenshots as relevant._
 
+_If making changes to dbt models, please run the command `poetry run dbt run -s CHANGED_MODEL` and include the output in this section of the PR._
+
 ## Post-merge follow-ups
 
 _Document any actions that must be taken post-merge to deploy or otherwise implement the changes in this PR (for example, running a full refresh of some incremental model in dbt). If these actions will take more than a few hours after the merge or if they will be completed by someone other than the PR author, please create a dedicated follow-up issue and link it here to track resolution._