Logging.Entry: use dict form of AdditionalData

AdditionalData changed to be a dict[string, string] in PDI and
phosphor-logging.  Update the snmp trap code accordingly.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I08e533af0bd8f5c6c6bdc252207084de24489901
diff --git a/src/snmp_trap.cpp b/src/snmp_trap.cpp
index f7a4685..921d628 100644
--- a/src/snmp_trap.cpp
+++ b/src/snmp_trap.cpp
@@ -37,12 +37,12 @@
     auto sev = std::get<Entry::Level>(propMap.at("Severity"));
     auto isev = static_cast<uint8_t>(sev);
     auto message = std::get<std::string>(propMap.at("Message"));
-    auto additionalData =
-        std::get<std::vector<std::string>>(propMap.at("AdditionalData"));
-    for (auto& s : additionalData)
+    auto additionalData = std::get<std::map<std::string, std::string>>(
+        propMap.at("AdditionalData"));
+    for (auto& [k, v] : additionalData)
     {
         message.append(" ");
-        message.append(s);
+        message.append(k + "=" + v);
     }
     try
     {