Replace taskGraph.afterTask with an operation completion listener in Gradle 6.1+

[Vampire]

[yorlov]

Just to let you know, the plugin will not function on gradle 8.7 until this issue is rectified.

FAILURE: Build failed with an exception.

* What went wrong:
Configuration cache problems found in this build.

1 problem was found storing the configuration cache.
- Plugin 'net.researchgate.release': registration of listener on 'TaskExecutionGraph.afterTask' is unsupported
  See https://docs.gradle.org/8.6/userguide/configuration_cache.html#config_cache:requirements:build_listeners

[Vampire]

You mean the plugin will not function with 8.x if you enable configuration cache, which is not different in 8.7 from earlier versions.