Bump com.approvaltests:approvaltests from 26.5.0 to 26.6.0

Bumps [com.approvaltests:approvaltests](https://github.com/approvals/ApprovalTests.Java) from 26.5.0 to 26.6.0.
- [Release notes](https://github.com/approvals/ApprovalTests.Java/releases)
- [Changelog](https://github.com/approvals/ApprovalTests.Java/blob/master/internal_documentation/release.md)
- [Commits](approvals/ApprovalTests.Java@26.5.0...26.6.0)

---
updated-dependencies:
- dependency-name: com.approvaltests:approvaltests
  dependency-version: 26.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

build.gradle

@@ -17,7 +17,7 @@ dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib"
     implementation 'org.junit.jupiter:junit-jupiter:6.0.2'
     testRuntimeOnly 'org.junit.platform:junit-platform-launcher:6.0.2'
-    testImplementation("com.approvaltests:approvaltests:26.5.0")
+    testImplementation("com.approvaltests:approvaltests:26.6.0")
     testImplementation("com.google.code.gson:gson:2.13.2")
 }