Drop jCenter and publish only on Maven Central

[gotev]

Given the recent announcement made by JFrog: https://jfrog.com/blog/into-the-sunset-bintray-jcenter-gocenter-and-chartcenter/?utm_source=mkto&utm_medium=email&utm_campaign=bintray-sunset&utm_content=global-02-2021

Deploy pipelines have to be modified to publish directly on Maven Central: https://getstream.io/blog/publishing-libraries-to-mavencentral-2021/?s=09

Currently only the stablest versions of Upload Service are also published on Maven Central, therefore missing old versions will not be synced.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

[gotev]

this is the next step needed to publish the library again after jcenter closed new submissions. Aim to do it this weekend

[r0b0t3d]

Hi @gotev, could you release a new version in favor of this change?

[gotev]

What do you mean? Releases are on maven central for months now.

[r0b0t3d]

My bad. Thanks @gotev