Add status badge, rename basic build workflow.

.github/workflows/build.yml

@@ -3,7 +3,7 @@ on: [push]
 jobs:
   build:
     runs-on: ubuntu-latest
-    name: Basic build of the ZMK firmware
+    name: Build Test
     steps:
       # To use this repository's private action,
       # you must check out the repository

README.md

@@ -1,5 +1,7 @@
 # Zephyr Mechanical Keyboard (ZMK) Firmware
 
+![Build Test](https://github.com/zmkfirmware/zmk/workflows/Build%20Test/badge.svg)
+
 [![Netlify Status](https://api.netlify.com/api/v1/badges/942d61a9-87c0-4c23-9b51-f5ed0bce495d/deploy-status)](https://app.netlify.com/sites/zmk/deploys)
 
 This project is a complete work in progress, with absolutely nothing functioning yet. The goal is to explore a new MK firmware