ci: add Docker Compose setup step to GitHub Actions workflow

.github/workflows/main.yml

@@ -42,6 +42,11 @@ jobs:
     - name: Run unit tests
       run: make unit-test
 
+    - name: Set up Docker Compose
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y docker-compose
+    
     - name: Run coverage
       run: |
         mkdir -p coverage