[Enhancement]: Make README accessible via reate_template() API

[didier-durand]

Is your feature request related to a problem? Please describe.

I need to document via README the pod templates that I create via Python SDK

Currently, the API doesn't allow it:

def create_template(
    name: str,
    image_name: str,
    docker_start_cmd: str = None,
    container_disk_in_gb: int = 10,
    volume_in_gb: int = None,
    volume_mount_path: str = None,
    ports: str = None,
    env: dict = None,
    is_serverless: bool = False,
    registry_auth_id: str = None,
)

But the GraphQL spec at https://graphql-spec.runpod.io/#definition-PodTemplate as a readme parameter

Describe the solution you'd like

I'd like create_template()to be extended with a readme string parameter used to update the GraphQL

I am happy to submit the corresponding PR to add this code if it helps

Describe alternatives you've considered

There is no other way to fill README via API if readme is not accessible