Renamed InstanceOptions to just Options

[fahad19]

What's done

• Renamed InstanceOptions to just Options

Comparison

Before

package main

import (
    "github.com/featurevisor/featurevisor-go"
)

func main() {
    f := featurevisor.CreateInstance(featurevisor.InstanceOptions{
        Datafile: featurevisor.DatafileContent.FromJSON("{ ... }"),
    })
}

After

package main

import (
    "github.com/featurevisor/featurevisor-go"
)

func main() {
    f := featurevisor.CreateInstance(featurevisor.Options{
        Datafile: featurevisor.DatafileContent.FromJSON("{ ... }"),
    })
}