Bump org.gretty from 3.0.4 to 4.1.6

Bumps org.gretty from 3.0.4 to 4.1.6.

---
updated-dependencies:
- dependency-name: org.gretty
  dependency-version: 4.1.6
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id 'java'
-    id 'org.gretty' version '3.0.4'
+    id 'org.gretty' version '4.1.6'
     id 'idea'
     id 'war'
     id 'groovy'