Update badges.

Author: netomi

README.md

@@ -3,7 +3,8 @@ A sudoku solver / generator.
 ============================
 
 ![Build status](https://github.com/netomi/sudoku-solver/workflows/build-status/badge.svg)
-[ ![Download](https://api.bintray.com/packages/netomi/sudoku/com.github.netomi.sudoku%3Asudoku-solver/images/download.svg?version=0.1) ](https://bintray.com/netomi/sudoku/com.github.netomi.sudoku%3Asudoku-solver/0.1/link)
+[![Sonatype Nexus (Snapshots)](https://img.shields.io/nexus/s/https/oss.sonatype.org/com.github.netomi.sudoku/sudoku-solver.svg)](https://oss.sonatype.org/content/repositories/snapshots/com/github/netomi/sudoku/sudoku-solver/)
+[![GitHub license](https://img.shields.io/github/license/netomi/sudoku-solver)](https://github.com/netomi/sudoku-solver/blob/master/LICENSE)
 
 This repository contains a multiplatform library written in
 Kotlin to solve and generate sudoku puzzles.