Add GitHub Actions (#442)

* Add workflow

* Add status badge

.github/workflows/maven.yml

@@ -0,0 +1,20 @@
+name: Maven Package
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 8
+        uses: actions/setup-java@v2
+        with:
+          java-version: '8'
+          distribution: 'adopt'
+      - name: Build with Maven
+        run: mvn -B package --file pom.xml

README.md

@@ -1,5 +1,7 @@
 Hypixel Public API (Java)
 ======
+[![Maven Package](https://github.com/HypixelDev/PublicAPI/actions/workflows/maven.yml/badge.svg)](https://github.com/HypixelDev/PublicAPI/actions/workflows/maven.yml)
+
 This is a Java implementation of the Hypixel API. For discussing the API, requesting help or suggestions you can use the
 GitHub [Discussions](https://github.com/HypixelDev/PublicAPI/discussions).