Add GET method for Triggers

Added GET method for retrieving details of individual Trigger searched
by given Trigger name, details are extracted from Telemetry service

Tested:
- Added single Trigger and requested result from bmcweb via
  /redfish/v1/TelemetryService/Triggers/<triggername>
- Added multiple Triggers numeric and discrete with various parameters
  (empty, non-empty), and requested results from bmcweb via
  /redfish/v1/TelemetryService/Triggers/<triggername>
- Verified uris /redfish/v1/TelemetryService/Triggers/<triggername> by
  using Redfish-Service-Validator (all passed)

Signed-off-by: Lukasz Kazmierczak <lukasz.kazmierczak@intel.com>
Change-Id: I1c966b2f792324cc6f6a8784ad18a683e5ce7bd9
diff --git a/scripts/update_schemas.py b/scripts/update_schemas.py
index 63b441e..eb6318f 100755
--- a/scripts/update_schemas.py
+++ b/scripts/update_schemas.py
@@ -93,6 +93,7 @@
     'TaskService',
     'TelemetryService',
     'Thermal',
+    'Triggers',
     'TriggersCollection',
     'UpdateService',
     'VLanNetworkInterfaceCollection',