Addign reference to StackOverflow entry

Author: MrCsabaToth

README.md

@@ -1,2 +1,4 @@
 # EcoAgentFunction
 Glue code: Cloud Function to call Agent Builder agent (DialogFlow CX under the hood)
+
+[Related Stack Overflow entry](https://stackoverflow.com/questions/78344470/how-to-have-a-programmatical-conversation-with-an-agent-created-by-agent-builder/)