Added validation for trigger time_range

Author: kumar-avijit

sumologic/resource_sumologic_monitors_library_monitor.go

@@ -104,6 +104,7 @@ func resourceSumologicMonitorsLibraryMonitor() *schema.Resource {
 						"time_range": {
 							Type:     schema.TypeString,
 							Optional: true,
+							ValidateFunc: validation.StringInSlice([]string{"5m","10m","15m","30m","60m","1h","3h","6h","12h","24h","1d"}, false),
 						},
 						"trigger_source": {
 							Type:     schema.TypeString,