Modify severity text for discrete Triggers

Changed text string representation of severity for discrete Triggers,
needed to conform to Redfish Schema:
https://redfish.dmtf.org/schemas/v1/Triggers.v1_1_4.json AND
https://redfish.dmtf.org/schemas/v1/Resource.json#/definitions/Health

Tested:
- Creating various discrete Triggers and retrieving information about
  them from Telemetry (via bmcweb by POST/GET, via QEMU cli by busctl)
- Verifying retrieved Redfish data by using Redfish-Service-Validator

Signed-off-by: Lukasz Kazmierczak <lukasz.kazmierczak@intel.com>
Change-Id: Ic24cb163a3e7a7ab6228999f6f9d71f6277c7d78
diff --git a/src/types/trigger_types.hpp b/src/types/trigger_types.hpp
index 6721e68..4b6e150 100644
--- a/src/types/trigger_types.hpp
+++ b/src/types/trigger_types.hpp
@@ -23,7 +23,7 @@
 namespace details
 {
 constexpr std::array<std::pair<std::string_view, Severity>, 3>
-    convDataSeverity = {std::make_pair("Ok", Severity::ok),
+    convDataSeverity = {std::make_pair("OK", Severity::ok),
                         std::make_pair("Warning", Severity::warning),
                         std::make_pair("Critical", Severity::critical)};