add automatic jar builder

.forgejo/workflows/build-jars.yml

@@ -0,0 +1,24 @@
+on: [push]
+jobs:
+  makeOslo:
+    name: Build BaseBand-Oslo
+
+    runs-on: 'docker'
+
+    steps:
+    - name: Setup Java
+      uses: https://github.com/actions/setup-java@v4
+      with:
+        distribution: 'adopt'
+        java-version: 8
+    - name: Checkout
+      uses: actions/checkout@v4
+    - name: Initialize Gradle
+      uses: https://github.com/gradle/actions/setup-gradle@v3
+    - name: Build
+      run: ./gradlew --no-daemon Client:build
+    - name: Upload
+      uses: forgejo/upload-artifact@v4
+      with:
+        name: BaseBand-Oslo.jar
+        path: Client/build/libs/BaseBand-Oslo.jar