update plugin and dependency versions

This PR contains the following changes:
  - update dependency versions: not I only did a minor update of the maven-plugin-api (to 3.0.5 and not upgrade to 3.1.1)
  - update plugin versions
  - fix a deprecation in ScriptCoverageStatistics; related to updating Guava
  - fix previously deprecated, now missing Proxy.setHttpsProxy(...) in GenericInstrumentingBrowser and InstrumentingProxyServerIT; related to updating Selenium