Add update_subscription to relay_manager.

[bitsperity]

Hey Guys, I just saw that update_subscription is implemented in the relay, but not in the manager.

def update_subscription(self, id: str, filters: Filters):
for relay in self.relays.values():
relay.update_subscription(id, filters)

If I create a branch locally and push it, I get permission denied. How can I contribute? Would like to add this and future PR. Would be happy for some advice!

[PlebeiusGaragicus]

Fork the project to create your own repo, push the changes to that repo, then submit a pull request back to this repo. You can't push changes to this repo because you don't own it. Pull requests are what you're looking for.