Bump com.icegreen:greenmail from 2.1.5 to 2.1.6

Bumps [com.icegreen:greenmail](https://github.com/greenmail-mail-test/greenmail) from 2.1.5 to 2.1.6.
- [Release notes](https://github.com/greenmail-mail-test/greenmail/releases)
- [Commits](greenmail-mail-test/greenmail@release-2.1.5...release-2.1.6)

---
updated-dependencies:
- dependency-name: com.icegreen:greenmail
  dependency-version: 2.1.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

build.gradle

@@ -85,7 +85,7 @@ dependencies {
     testImplementation 'com.tngtech.archunit:archunit-junit5:1.4.1'
     testImplementation 'org.assertj:assertj-core:3.27.5'
     testImplementation 'io.rest-assured:rest-assured:5.5.6'
-    testImplementation 'com.icegreen:greenmail:2.1.5'
+    testImplementation 'com.icegreen:greenmail:2.1.6'
     testImplementation 'org.awaitility:awaitility:4.3.0'
 }