Fix unused require and parameter warnings

This commit removes two minor compiler warnings:

- Remove unused "require Logger" from MapFilter module
- Prefix unused opts parameter with underscore in FakeDebounce test
  support module

These warnings don't affect functionality but create noise in the test
output.

Author: jeffkreeftmeijer

lib/appsignal/utils/map_filter.ex

@@ -1,6 +1,5 @@
 defmodule Appsignal.Utils.MapFilter do
   @moduledoc false
-  require Logger
 
   # Phoenix parameter filtering adapted from the Phoenix Framework.
   # Copyright (c) 2014 Chris McCord - Licensed under MIT

test/support/appsignal/fake_debounce.ex

@@ -1,7 +1,7 @@
 defmodule Appsignal.FakeDebounce do
   use Agent
 
-  def start_link(opts \\ nil) do
+  def start_link(_opts \\ nil) do
     Agent.start_link(
       # Since `nil` is a valid value for `last_transmission_milliseconds`,
       # we use `:never_called` to differentiate when the function has