Allow HTTPX methods on the client

[balevine]

Trying to access a couple of httpx methods yields errors.

For example, calling

client =  Httpsensible::Client.new
client.with(timeout: { connect_timeout: 10, request_timeout: 3 }).get("/")

returns

NoMethodError (undefined method `with_timeout' for an instance of Httpsensible::Client)

The same is true for client.request(requests).

However, accessing the underlying httpx client provides access to those methods. This works:

client =  Httpsensible::Client.new
client.client.with(timeout: { connect_timeout: 10, request_timeout: 3 }).request(requests)

Ideally, I think those methods would be accessible to the httpsensible client directly.