docs: adding Apache 2.0 license

[leogr]

Context

Falcosidekick was created by @Issif , and MIT licensed it. In 2019, Falcosidekick was contributed to the falcosecurity organization.

During the last year, we reaudited our project licenses and decided to add Apache2 SPDX ID, since Apache2 license is required by our governance. While doing that, we just added Apache2 to header files and did not update the LICENSE file in the root.

Proposal

To address this properly, before the upcoming release of Falcosidekick 2.29, I propose to dual license Falcosidekick under both MIT and Apache 2.0 and adequately document that in the LICENSE file and file headers. By doing so, the Apache 2.0 license is being added as an option rather than a replacement. Users can choose which license to follow. This does not inherently negate or override the terms of the MIT license.

Action items

• Use SPDX-License-Identifier: MIT OR Apache-2.0
• Add Apache 2.0 to the LICENSE file along with MIT
• Add the Copyright (C) 2024 The Falco Authors statement where missing

/assign