Bump testng from 7.5 to 7.6.0

Bumps [testng](https://github.com/cbeust/testng) from 7.5 to 7.6.0.
- [Release notes](https://github.com/cbeust/testng/releases)
- [Changelog](https://github.com/cbeust/testng/blob/master/CHANGES.txt)
- [Commits](https://github.com/cbeust/testng/commits)

---
updated-dependencies:
- dependency-name: org.testng:testng
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

build.gradle

@@ -45,7 +45,7 @@ repositories {
 dependencies {
     testCompile group: 'junit', name: 'junit', version: '4.13.2'
     testCompile 'org.reactivestreams:reactive-streams-tck-flow:1.0.4'
-    testCompile group: 'org.testng', name: 'testng', version: '7.5'
+    testCompile group: 'org.testng', name: 'testng', version: '7.6.0'
 }
 
 [compileJava, compileTestJava]*.options*.compilerArgs << "-parameters"