added ${gamengine.version} instead of specific version

Author: Butanium

playground/extensions/extensions-1-tools.md

@@ -20,12 +20,12 @@ Example of a project using the Graphic Entity Module and the End Screen Module:
 <dependency>
 	<groupId>com.codingame.gameengine</groupId>
 	<artifactId>module-entities</artifactId>
-	<version>4.3.0</version>
+	<version>${gamengine.version}</version>
 </dependency>
 <dependency>
 	<groupId>com.codingame.gameengine</groupId>
 	<artifactId>module-endscreen</artifactId>
-	<version>4.3.0</version>
+	<version>${gamengine.version}</version>
 </dependency>
 ```
 `config.js`
@@ -54,4 +54,4 @@ import { CustomModule } from './modules/custom/CustomModule.js';
 export const modules = [
 	GraphicEntityModule,
 	CustomModule
-];
+];