Update README example for modern Dart conventions (#64)

diff --git a/README.md b/README.md
index 04e0359..a5f082d 100644
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@
 2\. Install pub packages
 
 ```
-pub install
+dart pub install
 ```
 
 3\. Add the following import:
@@ -56,10 +56,10 @@
 
 ## Example
 
-Create a dart file in the [`benchmark/`](https://www.dartlang.org/tools/pub/package-layout#tests-and-benchmarks)
+Create a dart file in the [`benchmark/`](https://dart.dev/tools/pub/package-layout#tests-and-benchmarks)
 folder of your package.
 
-```
+```dart
 // Import BenchmarkBase class.
 import 'package:benchmark_harness/benchmark_harness.dart';
 
@@ -68,24 +68,23 @@
   const TemplateBenchmark() : super('Template');
 
   static void main() {
-    TemplateBenchmark().report();
+    const TemplateBenchmark().report();
   }
 
   // The benchmark code.
   @override
-  void run() {
-  }
+  void run() {}
 
   // Not measured setup code executed prior to the benchmark runs.
   @override
-  void setup() { }
+  void setup() {}
 
   // Not measured teardown code executed after the benchmark runs.
   @override
-  void teardown() { }
+  void teardown() {}
 }
 
-main() {
+void main() {
   // Run TemplateBenchmark
   TemplateBenchmark.main();
 }