Handle more Redis RESP3 protocol pieces

This passes the "minimum protocol version" along in the reply and adds
support for attributes, which were added relatively recently.

testing/btest/scripts/base/protocols/redis/attributes.zeek

@@ -0,0 +1,19 @@
+# @TEST-DOC: Test Redis protocol handling with replies with attributes
+# @TEST-REQUIRES: have-spicy
+#
+# @TEST-EXEC: zeek -b -r $TRACES/redis/attr.pcap %INPUT >output
+# @TEST-EXEC: btest-diff output
+# @TEST-EXEC: btest-diff redis.log
+
+# IMPORTANT: The test data was made synthetically, since real commands that
+# return attributes may be version-specific. Real traffic would be better.
+
+@load base/protocols/redis
+
+event Redis::reply(c: connection, data: Redis::ReplyData)
+	{
+	if ( ! data?$attributes )
+		print "Got data:", data$value;
+	else
+		print "Got data:", data$value, "with attributes:", data$attributes;
+	}