[BUG] Consul agent_service_maintenance using incorrect HTTP method

Description
The agent_service_maintenance function int he consul module uses an HTTP GET call rather than an HTTP PUT call as defined in the API documentation https://www.consul.io/api-docs/agent/service#enable-maintenance-mode.

Setup
Set up a salt minion with the consul agent installed locally and a service running that is registered in consul.

Steps to Reproduce the behavior
Run the consul module using the command

salt '*' consul.agent_service_maintenance consul_url='http://localhost:8500' serviceid='redis' enable='True' reason='Down for upgrade'

Expected behavior
The consul service is set into maintenance mode

Additional context
The relevant context in the source code is here https://github.com/saltstack/salt/blob/f1da86977d0d690c621c33e1c2ca8eecc261c03c/salt/modules/consul.py#L1164 where the method parameter is omitted which makes it default to HTTP GET.

Start in salt/modules/consul.py around line 1164 and compare the agent_service_maintenance request with Consul's enable-maintenance-mode API documentation. Reproduce it with the provided salt command against a local Consul agent, then verify that the service enters maintenance mode as expected.