[Feature] Include the Sha in create webhooks

[Beanow]

For Drone CI integrations, having the commit Sha in a create (tag) webhook event is being relied on for docker builds. See drone-plugins/drone-docker#229

Please add this to the payload.

Git tea does make this available, visible here https://github.com/go-gitea/go-sdk/blob/2858b80da5f75fa2eea3fcf3205a5e6fd16da0ec/gitea/hook.go#L196

[unknwon]

Closed by #104