docs(pull_request_template): new sample JIRA task

XYZ is obviously wrong. 123 could be skipped.

So, use XYZ, to better suggest change.

.github/pull_request_template.md

@@ -5,7 +5,7 @@
 ## Related
 
 <!--
-- [FP-123](https://jira.tacc.utexas.edu/browse/FP-123)
+- [CMD-XYZ](https://tacc-main.atlassian.net/browse/CMD-XYZ)
 - requires https://github.com/TACC/Core-CMS/pull/5
 - required by https://github.com/TACC/Core-CMS-Resources/pull/117
 -->…