Update some dependencies.
Update some dependencies.

- junit:junit ........................................... 4.13 -> 4.13.2
- org.apache.logging.log4j:log4j-core .................. 2.8.2 -> 2.14.1
- org.apache.logging.log4j:log4j-slf4j-impl ............ 2.8.2 -> 2.14.1
- org.conscrypt:conscrypt-openjdk-uber .................. 2.2.1 -> 2.5.2
- org.mockito:mockito-core ............................. 3.10.0 -> 4.0.0
- io.reactivex.rxjava2:rxjava .......................... 2.2.8 -> 2.2.21

apache/httpcore,apache/httpcore,apache/httpcomponents-core