Readme missing crucial documentation of setting Package.swift

[rcherukuri12]

Problem: package name and import names differ.
Package name : SwiftXGBoost
import name : XGBoost

so Package.swift needs:
.package(name:"SwiftXGBoost", ...)
and
target needs:
.dependencies : [ .product(name:"XGBoost", package:"SWiftXGBoost")]

[kongzii]

Hi,

is there any particular reason why is this a problem?

I am using it like this and it works just fine.

    dependencies: [
        .package(url: "https://github.com/kongzii/SwiftXGBoost.git", .exact("0.9.0-tensorflow")),
    ],
    targets: [
        .target(
            name: "MyTarget",
            dependencies: [
                "XGBoost",
            ]
        ),