Use SPDX Identifier for Apache 2.0 license.
Use SPDX Identifier for Apache 2.0 license.

SPDX[1] is a standardized naming scheme for open-source licenses, making it
easier to track license dependencies in software.

This is also endorsed by the Composer project itself[2].

[1] https://spdx.org/licenses/
[2] https://getcomposer.org/doc/04-schema.md#license

Signed-off-by: Jacob Kiers <f862f167b85d41b225785c70d70808bc7337c1fe@alphacomm.nl>

marcelog/PAGI