Merge pull request #1430 from NGEET/glemieux-patch-1

Update PULL_REQUEST_TEMPLATE with sp mode b4b check

Author: glemieux

.github/PULL_REQUEST_TEMPLATE.md

@@ -28,6 +28,9 @@ All checklist items must be checked to enable merging this pull request:
 *Integrator*
 - [ ] FATES PASS/FAIL regression tests were run
 - [ ] Evaluation of test results for answer changes was performed and results provided
+- [ ] FATES-CLM6 Code Freeze: satellite phenology regression tests are b4b
+
+*If satellite phenology regressions are **not** b4b, please hold merge and notify the FATES development team.*
 
 ### Documentation
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