Add missing license header to associator_logging_test

File introduced in #1623

Signed-off-by: Cristian Greco <cristian@regolo.cc>

Author: cristiangreco

pkg/job/maxdimassociator/associator_logging_test.go

@@ -1,3 +1,15 @@
+// Copyright 2024 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
 package maxdimassociator
 
 import (