Add quiet flag to podman-compose config

This skips printing and is useful for validating config files.

Signed-off-by: Ian Fijolek <ian@iamthefij.com>

tests/integration/profile/test_podman_compose_config.py

@@ -80,3 +80,20 @@ class TestComposeConfig(unittest.TestCase, RunSubprocessMixin):
             actual_services[service] = service in actual_output
 
         self.assertEqual(expected_services, actual_services)
+
+    def test_config_quiet(self):
+        """
+        Tests podman-compose config command with the --quiet flag.
+        """
+        config_cmd = [
+            "coverage",
+            "run",
+            podman_compose_path(),
+            "-f",
+            profile_compose_file(),
+            "config",
+            "--quiet",
+        ]
+
+        out, _ = self.run_subprocess_assert_returncode(config_cmd)
+        self.assertEqual(out.decode("utf-8"), "")