maven sample, add mising runtime scope

src/docs/asciidoc/jme3/maven.adoc

@@ -194,6 +194,7 @@ dependencies {
       <groupId>${jm3_g}</groupId>
       <artifactId>jme3-lwjgl</artifactId>
       <version>${jme3_v}</version>
+      <scope>runtime</scope>
     </dependency>
   </dependencies>
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