Update gradle with Reader SDK 1.3.0 requirements.

[WhatsEmo]

[CLAassistant]

All committers have signed the CLA.

[hukid]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution. You have signed the CLA already but the status is still pending? Let us recheck it.

@WhatsEmo please sign the CLA.

[hukid]

Have you verified this will work? I don't see following configuration added:

compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }