Update CustomRuleThresholdChange.json

Changing the threshold from 50 to .50 so it reflects as 50% and NOT 5000%

Author: sqlworldwide

samples/manage/sql-assessment-api/notebooks/CustomizationSamples/CustomRuleThresholdChange.json

@@ -6,7 +6,7 @@
         {
             "id": "DBSpaceAvailable",
             "itemType": "override",
-            "threshold": 50
+            "threshold": .50
         }
     ]
 }