Revert "EXP: update to Sentry 12.0"

This reverts commit 657d82b021.

lib/sentry/finch_client.ex

@@ -0,0 +1,25 @@
+defmodule Sentry.FinchClient do
+  @moduledoc """
+  Defines a small shim to use `Finch` as a `Sentry.HTTPClient`.
+  """
+
+  @behaviour Sentry.HTTPClient
+
+  @impl true
+  def child_spec do
+    Finch.child_spec(name: Sentry.Finch)
+  end
+
+  @impl true
+  def post(url, headers, body) do
+    request = Finch.build(:post, url, headers, body)
+
+    case Finch.request(request, Sentry.Finch) do
+      {:ok, response} ->
+        {:ok, response.status, response.headers, response.body}
+
+      error ->
+        error
+    end
+  end
+end