Bump mockito-core from 3.7.7 to 3.9.0 (#135)

Bumps [mockito-core](https://github.com/mockito/mockito) from 3.7.7 to 3.9.0.
- [Release notes](https://github.com/mockito/mockito/releases)
- [Commits](mockito/mockito@v3.7.7...v3.9.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle

@@ -88,5 +88,5 @@ dependencies {
     compile group: 'org.apache.commons', name: 'commons-lang3', version: '3.11'
     testCompile group: 'junit', name: 'junit', version:'4.13.2'
     testCompile group: 'org.slf4j', name: 'slf4j-simple', version:'1.7.30'
-    testCompile group: 'org.mockito', name: 'mockito-core', version:'3.7.7'
+    testCompile group: 'org.mockito', name: 'mockito-core', version:'3.9.0'
 }