fix: Makefile license header duplication

Signed-off-by: Ian Lewis <ianmlewis@gmail.com>

Makefile

@@ -12,20 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Copyright 2023 Google LLC
-#
-# 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.
-
 SHELL := /bin/bash
 OUTPUT_FORMAT ?= $(shell if [ "${GITHUB_ACTIONS}" == "true" ]; then echo "github"; else echo ""; fi)