fix: update trigger name

[liweitian]

Description

update trigger name Conversation started to Greeting (ConversationUpdate)

Task Item

Closes #1302

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have functionally tested my change

Screenshots

Please include screenshots or gifs if your PR include UX changes.

[boydc2014]

Looks good. Looks like you updated all the references, code, doc, sample, pretty thoughtful. Just want to confirm one thing, only 3 templates are using OnConverstaionUpdate right?

[liweitian]

Looks good. Looks like you updated all the references, code, doc, sample, pretty thoughtful. Just want to confirm one thing, only 3 templates are using OnConverstaionUpdate right?

Did a global search. So yes. Only three templates are using it.