Switch CI system from CircleCI to GitHub actions

.github/workflows/main.yml

@@ -0,0 +1,26 @@
+name: Maven Build
+
+on: [push]
+
+jobs:
+  build:
+    name: Build application
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+      - name: Prepare JDK
+        uses: actions/setup-java@v3
+        with:
+          java-version: 21
+          distribution: temurin
+          cache: maven
+      - name: Build application
+        run: mvn --batch-mode clean package
+      - name: Publish test results
+        uses: dorny/test-reporter@v1
+        if: success() || failure()
+        with:
+          name: JUnit test results
+          path: target/surefire-reports/*.xml
+          reporter: java-junit

README.md

@@ -1,7 +1,7 @@
 # FimaSu (Finanzmanager Support)
 
 [![License](http://img.shields.io/:license-apache-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0)
-[![Build](https://img.shields.io/circleci/build/github/perdian/fimasu/master)](https://circleci.com/gh/perdian/fimasu)
+[![Build](https://img.shields.io/github/actions/workflow/status/perdian/fimasu/main.yml)](https://github.com/perdian/mp3tagtiger/actions/workflows/main.yml)
 
 Quick solution to allow the generation of a QIF file ([Quicken Interchange Format](https://de.wikipedia.org/wiki/Quicken_Interchange_Format)).