Add ManagerDiagnosticData schema

This change adds the ManagerDiagnosticData schema files.

Tested: ran Redfish Service Validator:
                                       + Manager
                                      Diagnostic
                              2021.4        Data

metadataNamespaces:             2388        2390
pass:                           3249        3274
passAction:                        8           8
passGet:                         121         123
passRedfishUri:                  115         117
skipNoSchema:                      3           3
skipOptional:                   2184        2198
warnDeprecated:                  315         315
warningPresent:                   11          11
Validation has:            succeeded   succeeded

curl -k
https://$bmc/redfish/v1/JsonSchema/ManagerDiagnosticData/\
ManagerDiagnosticData.json
...
    "title": "#ManagerDiagnosticData.v1_0_0.ManagerDiagnosticData"
}

Signed-off-by: Sui Chen <suichen@google.com>
Change-Id: I0d86b45350475771acdd492a98018156f8c819dd
diff --git a/scripts/update_schemas.py b/scripts/update_schemas.py
index 509fb7d..f324967 100755
--- a/scripts/update_schemas.py
+++ b/scripts/update_schemas.py
@@ -47,6 +47,7 @@
     'ManagerAccount',
     'ManagerAccountCollection',
     'ManagerCollection',
+    'ManagerDiagnosticData',
     'ManagerNetworkProtocol',
     'Memory',
     'MemoryCollection',