Task: signJar FAILED when trying to gradle assemble

I am trying to use a tool (PharmCAT.org) that utilizes gradle but it seems that it turns up with the following error when “gradle assemble” or “./gradlew assemble” was used:

Task :signJar FAILED

FAILURE: Build failed with an exception.

  • What went wrong:
    Execution failed for task ‘:signJar’.

Cannot perform signing task ‘:signJar’ because it has no configured signatory

  • Try:
    Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

The following is the result for stacktrace:

Task :compileJava UP-TO-DATE
Task :processResources UP-TO-DATE
Task :classes UP-TO-DATE
Task :osgiClasses UP-TO-DATE
Task :jar UP-TO-DATE
Task :startScripts UP-TO-DATE
Task :distTar UP-TO-DATE
Task :distZip UP-TO-DATE
Task :javadoc UP-TO-DATE
Task :javadocJar UP-TO-DATE
Task :shadowJar UP-TO-DATE
Task :startShadowScripts UP-TO-DATE
Task :shadowDistTar UP-TO-DATE
Task :shadowDistZip UP-TO-DATE
Task :signJar FAILED

Deprecated Gradle features were used in this build, making it incompatible with Gradle 6.0.
Use ‘–warning-mode all’ to show the individual deprecation warnings.
See https://docs.gradle.org/5.5/userguide/command_line_interface.html#sec:command_line_warnings
14 actionable tasks: 1 executed, 13 up-to-date

Any suggestions in order to improve my post is appreciated.