Add header to swiftly-install script to satisfy soundness.sh

Author: marcprux

swiftly-install

@@ -1,4 +1,18 @@
-#!/bin/bash -e
+#!/bin/bash
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) 2025 Apple Inc. and the Swift.org project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.txt for the list of Swift.org project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
+
 # Install script for Swiftly
 # Usage: curl -fsSL https://swift.org/swiftly-install | sh
 OS_NAME=$(uname -s)