Upgrade okhttp3 to 3.6.0
Upgrade okhttp3 to 3.6.0

Also add com.squareup.okhttp3:logging-interceptor dependency management.

fixes gh-1752

ryanjbaxter/spring-cloud-netflix,sfat/spring-cloud-netflix,sfat/spring-cloud-netflix,shuiky/spring-cloud-netflix,sfat/spring-cloud-netflix,ryanjbaxter/spring-cloud-netflix,brenuart/spring-cloud-netflix,brenuart/spring-cloud-netflix,shuiky/spring-cloud-netflix,brenuart/spring-cloud-netflix,joshiste/spring-cloud-netflix,ryanjbaxter/spring-cloud-netflix,joshiste/spring-cloud-netflix,ryanjbaxter/spring-cloud-netflix,bijukunjummen/spring-cloud-netflix,bijukunjummen/spring-cloud-netflix,shuiky/spring-cloud-netflix,sfat/spring-cloud-netflix,spring-cloud/spring-cloud-netflix,joshiste/spring-cloud-netflix,shuiky/spring-cloud-netflix,spring-cloud/spring-cloud-netflix,shuiky/spring-cloud-netflix,bijukunjummen/spring-cloud-netflix,sfat/spring-cloud-netflix,bijukunjummen/spring-cloud-netflix,joshiste/spring-cloud-netflix,ryanjbaxter/spring-cloud-netflix,joshiste/spring-cloud-netflix,brenuart/spring-cloud-netflix,bijukunjummen/spring-cloud-netflix,brenuart/spring-cloud-netflix