eve-parity: handle arrays of scalars

And add an example with "client_alpns".

etc/schema.json

@@ -6774,6 +6774,9 @@
                 "client_alpns": {
                     "description": "TLS client ALPN field(s)",
                     "type": "array",
+		    "suricata": {
+			"keywords": ["tls.alpn"]
+		    },
                     "items": {
                         "type": "string"
                     }

scripts/eve-parity.py

@@ -118,9 +118,8 @@ def load_schema():
                             ),
                         )
                     else:
-                        # May want to warn that this array has no properties.
                         key = ".".join(path + [name])
-                        keys[key] = {}
+                        keys[key] = props.get("suricata", {})
                 else:
                     # May want to warn that this array has no items.
                     key = ".".join(path + [name])