Remove deprecated logger attribute in Appsignal.AuthCheck

As deprecated in #245.
Part of #202.

lib/appsignal/auth_check.rb

@@ -20,16 +20,10 @@ class AuthCheck
     # https://push.appsignal.com/1/auth
     ACTION = "auth".freeze
 
-    attr_reader :config, :logger
+    attr_reader :config
 
-    def initialize(config, logger = nil)
+    def initialize(config)
       @config = config
-      if logger # rubocop:disable Style/GuardClause
-        Appsignal::Utils::DeprecationMessage.message \
-          "`Appsignal::AuthCheck.new`'s `logger` argument will be removed " \
-          "in the next major version. Please configure the logger " \
-          "using `Appsignal.logger`."
-      end
     end
 
     # Perform push api validation request and return response status code.

spec/lib/appsignal/auth_check_spec.rb

@@ -28,29 +28,6 @@ def build_uri_query_string(hash)
     end.join("&")
   end
 
-  describe ".new" do
-    describe "with logger argument" do
-      let(:err_stream) { std_stream }
-      let(:stderr) { err_stream.read }
-      let(:log_stream) { std_stream }
-      let(:log) { log_contents(log_stream) }
-
-      it "logs and prints a deprecation message" do
-        Appsignal.logger = test_logger(log_stream)
-
-        capture_std_streams(std_stream, err_stream) do
-          Appsignal::AuthCheck.new(config, Appsignal.logger)
-        end
-
-        deprecation_message =
-          "`Appsignal::AuthCheck.new`'s `logger` argument " \
-          "will be removed in the next major version."
-        expect(stderr).to include "appsignal WARNING: #{deprecation_message}"
-        expect(log).to contains_log :warn, deprecation_message
-      end
-    end
-  end
-
   describe "#perform" do
     subject { auth_check.perform }