Change deployments from Bintray to Maven Central and Github packages

[goneall]

Bintray is retiring their service on May 1. Prior to retirement, we need to start publishing an alternative package storage provider.

Suggest both Maven Central and Github Packages.

This can be automated using Github actions. See https://docs.github.com/en/actions/guides/publishing-java-packages-with-maven#publishing-packages-to-the-maven-central-repository-and-github-packages

[stevespringett]

@goneall I noticed that 0.0.6 was deployed to Central, but 1.0.0 is not.
https://repo1.maven.org/maven2/org/spdx/tools-java/

[goneall]

@stevespringett The tools-java is a separate package which uses the library (spdx-java-library) as a dependency. I'm working my way through updating all the Java libraries to a 1.0.0 release - it should be available within the next few days.

[stevespringett]

Ah - my mistake. I see 1.0.0 of https://repo1.maven.org/maven2/org/spdx/java-spdx-library/ is infact available on Central.

[goneall]

Resolved with PR #41