Bump mysql-connector-java in /modules/junit-jupiter

Bumps [mysql-connector-java](https://github.com/mysql/mysql-connector-j) from 8.0.15 to 8.0.16.
- [Release notes](https://github.com/mysql/mysql-connector-j/releases)
- [Changelog](https://github.com/mysql/mysql-connector-j/blob/release/8.0/CHANGES)
- [Commits](mysql/mysql-connector-j@8.0.15...8.0.16)

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

modules/junit-jupiter/build.gradle

@@ -11,7 +11,7 @@ dependencies {
     testCompile 'org.apache.httpcomponents:httpclient:4.5.8'
 
     testRuntime 'org.postgresql:postgresql:42.2.5'
-    testRuntime 'mysql:mysql-connector-java:8.0.15'
+    testRuntime 'mysql:mysql-connector-java:8.0.16'
     testRuntime 'org.junit.jupiter:junit-jupiter-engine:5.4.2'
 }