dont send auth header if nil and remove push_image from api

docker_engine_api/api/image.ex

@@ -533,47 +533,6 @@ defmodule DockerEngineAPI.Api.Image do
     ])
   end
 
-  @doc """
-  Push an image
-  Push an image to a registry.  If you wish to push an image on to a private registry, that image must already have a tag which references the registry. For example, `registry.example.com/myimage:latest`.  The push is cancelled if the HTTP connection is closed.
-
-  ### Parameters
-
-  - `connection` (DockerEngineAPI.Connection): Connection to server
-  - `name` (String.t): Image name or ID.
-  - `x_registry_auth` (String.t): A base64url-encoded auth configuration.  Refer to the [authentication section](#section/Authentication) for details.
-  - `opts` (keyword): Optional parameters
-    - `:tag` (String.t): The tag to associate with the image on the registry.
-
-  ### Returns
-
-  - `{:ok, nil}` on success
-  - `{:error, Tesla.Env.t}` on failure
-  """
-  @spec image_push(Tesla.Env.client, String.t, String.t, keyword()) :: {:ok, nil} | {:ok, DockerEngineAPI.Model.ErrorResponse.t} | {:error, Tesla.Env.t}
-  def image_push(connection, name, x_registry_auth, opts \\ []) do
-    optional_params = %{
-      :tag => :query
-    }
-
-    request =
-      %{}
-      |> method(:post)
-      |> url("/images/#{name}/push")
-      |> add_param(:headers, :"X-Registry-Auth", x_registry_auth)
-      |> add_optional_params(optional_params, opts)
-      |> ensure_body()
-      |> Enum.into([])
-
-    connection
-    |> Connection.request(request)
-    |> evaluate_response([
-      {200, false},
-      {404, DockerEngineAPI.Model.ErrorResponse},
-      {500, DockerEngineAPI.Model.ErrorResponse}
-    ])
-  end
-
   @doc """
   Search images
   Search for an image on Docker Hub.

lib/docker/api.ex

@@ -47,10 +47,11 @@ defmodule Testcontainers.Docker.Api do
 
   def pull_image(image, conn, opts \\ []) when is_binary(image) do
     auth = Keyword.get(opts, :auth, nil)
+    headers = if auth, do: ["X-Registry-Auth": auth], else: []
 
-    case Api.Image.image_create(conn,
-           fromImage: image,
-           "X-Registry-Auth": auth
+    case Api.Image.image_create(
+           conn,
+           Keyword.merge([fromImage: image], headers)
          ) do
       {:ok, %Tesla.Env{status: 200}} ->
         {:ok, nil}