fix wrong component id comment (#31)

Co-authored-by: Mrproliu <mrproliu@lagou.com>
diff --git a/lib/skywalking/tracer.lua b/lib/skywalking/tracer.lua
index 13c6571..83a0003 100644
--- a/lib/skywalking/tracer.lua
+++ b/lib/skywalking/tracer.lua
@@ -29,7 +29,7 @@
     tracingContext = TC.new(serviceName, serviceInstanceName)
 
     -- Constant pre-defined in SkyWalking main repo
-    -- 84 represents Nginx
+    -- 6000 represents Nginx
     local nginxComponentId = 6000
 
     local contextCarrier = {}