Add GitHub Actions workflow to build and test Java project

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/Smerty/jham?shareId=XXXX-XXXX-XXXX-XXXX).

.github/workflows/maven.yml

@@ -0,0 +1,36 @@
+name: Java CI with Maven
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+
+    - name: Set up JDK 11
+      uses: actions/setup-java@v2
+      with:
+        java-version: 11
+
+    - name: Cache Maven packages
+      uses: actions/cache@v2
+      with:
+        path: ~/.m2/repository
+        key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+        restore-keys: |
+          ${{ runner.os }}-maven-
+
+    - name: Build with Maven
+      run: mvn clean install
+
+    - name: Run unit tests
+      run: mvn test

README.md

@@ -1,9 +1,14 @@
 # jHam, Java Ham Radio Library
+[![Build Status](https://github.com/Smerty/jham/actions/workflows/maven.yml/badge.svg)](https://github.com/Smerty/jham/actions)
+
 Collection of utilities related to amateur radio.
 
 ## Using with Maven
     <dependency>
        <groupId>org.smerty</groupId>
        <artifactId>jham</artifactId>
        <version>1.0</version>
-    </dependency>
+    </dependency>
+
+## Automated Build Process
+This project uses GitHub Actions for continuous integration. The build process is triggered on push and pull request events for the `main` branch. The workflow file is located at `.github/workflows/maven.yml`.