Rename workflow name

Author: netomi

.github/workflows/gradle.yml

@@ -1,7 +1,7 @@
 # This workflow will build a Java project with Gradle
 # For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
 
-name: Java CI with Gradle
+name: build-status
 
 on:
   push:

README.md

@@ -2,7 +2,7 @@
 A sudoku solver / generator.
 ============================
 
-![Build status](https://github.com/netomi/sudoku-solver/workflows/gradle/badge.svg)
+![Build status](https://github.com/netomi/sudoku-solver/workflows/build-status/badge.svg)
 
 This repository contains a multiplatform library written in
 Kotlin to solve and generate sudoku puzzles.