Arcades MSBuild files all say they are Apache licenses, when the project is MIT license

[eerhardt]

All of our MSBuild files say

Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

Example:

arcade/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildStep.props

Line 1 in 9517895

<!-- Copyright (c) Microsoft. All Rights Reserved. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information. -->

However, the root license is MIT.

We should straighten the licensing out. It should all be MIT.

cc @tmat @markwilkie

[markwilkie]

@jcagme - note that Roslyn is Apache and Core is MIT, so please make sure we choose the correct license. (I think it's MIT....but not 100% sure)

[alexperovich]

These Apache licenses came from roslyn tools when I ported the changes.

[jcagme]

Talked to @jaredpar and we are ok to move files to MIT. Will work on the PR

[jcagme]

PTAL https://github.com/dotnet/arcade/pull/415/files