refactor!: rename `Atex.XRPC.OAuthClient.update_plug/2` to `update_conn/2`

CHANGELOG.md

···
 
 ## [Unreleased]
 
+### Breaking Changes
+
+- Rename `Atex.XRPC.OAuthClient.update_plug/2` to `update_conn/2`, to match the
+  naming of `from_conn/1`.
+
 ### Added
 
 - `Atex.OAuth.Plug` now requires a `:callback` option that is a MFA tuple

examples/oauth.ex

···
       IO.inspect(response, label: "output")
 
       conn
-      |> XRPC.OAuthClient.update_plug(client)
+      |> XRPC.OAuthClient.update_conn(client)
       |> send_resp(200, response.uri)
     else
       :error ->

lib/atex/xrpc/oauth_client.ex

···
   Ideally should be called at the end of routes where XRPC calls occur, in case
   the client has transparently refreshed, so that the user is always up to date.
   """
-  @spec update_plug(Plug.Conn.t(), t()) :: Plug.Conn.t()
-  def update_plug(%Plug.Conn{} = conn, %__MODULE__{} = client) do
+  @spec update_conn(Plug.Conn.t(), t()) :: Plug.Conn.t()
+  def update_conn(%Plug.Conn{} = conn, %__MODULE__{} = client) do
     Plug.Conn.put_session(conn, :atex_oauth, %{
       access_token: client.access_token,
       refresh_token: client.refresh_token,