Bump webdrivermanager from 3.4.0 to 3.6.1 (appium#1176)

Bumps [webdrivermanager](https://github.com/bonigarcia/webdrivermanager) from 3.4.0 to 3.6.1. - [Release notes](https://github.com/bonigarcia/webdrivermanager/releases) - [Changelog](https://github.com/bonigarcia/webdrivermanager/blob/master/CHANGELOG.md) - [Commits](bonigarcia/webdrivermanager@webdrivermanager-3.4.0...webdrivermanager-3.6.1) Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

build.gradle

@@ -75,7 +75,7 @@ dependencies {
 
  testCompile 'junit:junit:4.12'
  testCompile 'org.hamcrest:hamcrest:2.1'
- testCompile (group: 'io.github.bonigarcia', name: 'webdrivermanager', version: '3.4.0') {
+ testCompile (group: 'io.github.bonigarcia', name: 'webdrivermanager', version: '3.6.1') {
  exclude group: 'org.seleniumhq.selenium'
  }
 }