Published license identifier is not compliant with the SPDX license list

[mervyn-mccreight]

As for now the license is getting published as Apache 2 License but according to https://spdx.org/licenses/Apache-2.0.html the SPDX-identifier would be Apache-2.0.

It would be nice to align it to the SPDX-identifier, because this makes it easier for tools like e.g. Gradle plugins to detect the used license by relying on the SPDX license identifiers.

The published URL to the license is also not correct, as it just references as LICENSE.txt which is not an absolute path to the license file. IMO best would be to link to the official template of the used license, e.g. https://spdx.org/licenses/Apache-2.0.html or https://www.apache.org/licenses/LICENSE-2.0 respectively.