add missing compile options to build.gradle

[evanrich]

GenAI claims that your module is causing the following errors during flutter build apk:

warning: [options] source value 8 is obsolete and will be removed in a future release
warning: [options] target value 8 is obsolete and will be removed in a future release
warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.
3 warnings

it says you're missing the following in your android/build.gradle:

compileOptions {
    sourceCompatibility JavaVersion.VERSION_17
    targetCompatibility JavaVersion.VERSION_17
}

without this it defaults to Java 8. I don't know if this is true, but I had claude analyze my project's dependencies to identify which one was throwing the error and all the other had compileOptions declared, except this one. I am using image_cropper 11.0.0.