[EXAMPLES] renommer le nom du plugin sur la branche master

In the examples in the `master` branch, to use the plugin, the plugin name has not been renamed.

``` groovy
buildscript {
  apply from: '../version.gradle'

  repositories {
    mavenLocal()
   jcenter()
  }
  dependencies {
    classpath "fr.echoes.gradle.plugins:cpp-project-plugin:${cppPluginVersion('../../gradle.properties')}"
  }
}
```

renamed `cpp-project-plugin` in `gradle-cpp-plugin`
