Bump com.dorongold.task-tree from 1.5 to 2.1.0

Bumps com.dorongold.task-tree from 1.5 to 2.1.0.

---
updated-dependencies:
- dependency-name: com.dorongold.task-tree
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

build.gradle

@@ -27,7 +27,7 @@ plugins {
     id "de.undercouch.download" version '4.0.4'
     id 'edu.sc.seis.launch4j' version '2.4.6'
     id 'com.github.ben-manes.versions' version '0.39.0'
-    id "com.dorongold.task-tree" version '1.5'
+    id "com.dorongold.task-tree" version '2.1.0'
     id "edu.sc.seis.macAppBundle" version "2.3.0"
     id 'org.openjfx.javafxplugin' version '0.0.8'
     id 'org.beryx.runtime' version '1.12.5'