use badge for github workflow

.github/workflows/build.yaml

@@ -2,7 +2,9 @@ name: Build libnx
 
 on:
   push:
-    branches: [ master ]
+    branches:
+     - master
+     - workflow-badge
   pull_request:
 
 jobs:
@@ -18,4 +20,4 @@ jobs:
           persist-credentials: false
 
       - name: build
-        run: make -C nx
+        run: make -C nx -j2

README.md

@@ -1,7 +1,7 @@
 # Nintendo Switch AArch64-only userland library.
 Based on libctru.
 
-[![Build status](https://doozer.io/badge/switchbrew/libnx/buildstatus/master)](https://doozer.io/switchbrew/libnx)
+![Build status](https://github.com/switchbrew/libnx/actions/workflows/build.yaml/badge.svg)
 
 # Install instructions
 See [Switchbrew](https://switchbrew.org/wiki/Setting_up_Development_Environment).