Revise copyright and license information

Updated copyright notice and license header.

Author: mjburghard

MobiusCore/Source/Disposables/EmptyDisposable.swift

@@ -1,16 +1,5 @@
-// Copyright 2019-2024 Spotify AB.
-//
-// 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.
+// Copyright Spotify AB.
+// SPDX-License-Identifier: Apache-2.0
 
 import Foundation