Update image examples from 2-latest to 3-latest for Docker-based work pools #420
Description
Update Docker image examples from 2-latest to 3-latest for Docker-based work pools.
"example": "docker.io/prefecthq/prefect:2-latest"
needs updated to
"example": "docker.io/prefecthq/prefect:3-latest"
Not sure if this change requires new versions of the .json worker files or just updating the most recent versions.
