Update libraries and fix bundle support

[juliocbcotta]

Hi, I think I as able to fix the bundle problem with AS 4.1.1 by removing the casting. See : BuildFileProvider.kt

closes: https://github.com/cianru/huawei-publish-gradle-plugin/issues/16

While investigating I updated the libraries and gradle.

NOTES

• I made the plugin project a composite build, which means that you don't need to publish your plugin to a maven repo to test a change, gradle will replace the dependency in the samples by your "plugin" project. See settings.gradle

• To be able to run the project I had to remove the bintray user and password configs as I don't have it. Maybe it could be a good idea to make it optional for development cycle. I put them back to the project before commiting, but take a look at bintray-publish.gradle

• I fixed the path to the credentials in the sample2

• See: sample2/build.gradle

Sorry, the PR got really bigger than it needed to be, but the changes are quite simple in general.

[cosic]

@BugsBunnyBR Hi! Could you move PR to develop target branch instead of master. Please see https://github.com/cianru/huawei-publish-gradle-plugin/blob/master/CONTRIBUTING.md

[juliocbcotta]

@BugsBunnyBR Hi! Could you move PR to develop target branch instead of master. Please see https://github.com/cianru/huawei-publish-gradle-plugin/blob/master/CONTRIBUTING.md

done