[develop] Fix crontab bug for Cheyenne and Derecho, update PR templat…

…e for new platforms (#934)

The option to create an experiment with the option USE_CRON_TO_RELAUNCH=True is currently broken on Cheyenne and Derecho due to some bad python logic. This fixes that issue.

Also took the opportunity to update the PR template to include the new supported platforms (Derecho, Hercules, and Gaea C5)

.github/PULL_REQUEST_TEMPLATE

@@ -32,9 +32,12 @@
 
 - [ ] hera.intel
 - [ ] orion.intel
+- [ ] hercules.intel
 - [ ] cheyenne.intel
 - [ ] cheyenne.gnu
+- [ ] derecho.intel
 - [ ] gaea.intel
+- [ ] gaeac5.intel
 - [ ] jet.intel
 - [ ] wcoss2.intel
 - [ ] NOAA Cloud (indicate which platform)

ush/get_crontab_contents.py

@@ -35,11 +35,10 @@ def get_crontab_contents(called_from_cron, machine, debug):
     # themselves being called as cron jobs.  In that case, we must instead
     # call the system version of crontab at /usr/bin/crontab.
     #
+    crontab_cmd = "crontab"
     if machine == "CHEYENNE" or machine == "DERECHO":
         if called_from_cron:
             crontab_cmd = "/usr/bin/crontab"
-    else:
-        crontab_cmd = "crontab"
 
     print_info_msg(
         f"""