404 ao tentar usar thymeleaf | Spring Boot: Agilidade no desenvolvimento java com Spring

O instrutor ilustra o funcionamento do SpringFramework com @RequestBody, em seguida faz com que a rota retorne um template.

Ele remove a anotação @RequestBody, retorna o nome do template e cria o template com o nome index.html na pasta templates.

Não funcionou, então ele instalou o thymeleaf, daí funcionou. No meu caso mesmo após instalar o thymeleaf, ainda não funciona.

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listavip.Configuration

@SpringBootApplication
public class Configuration {

    public static void main(String[] args) {
        SpringApplication.run(Configuration.class, args);
    }

}

listavip.HomeController

@Controller
public class HomeController {

    @RequestMapping("/")
    public String ola() {
        return "index";
    }

}

src/main/resources/templates/index.html

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
    <title>ListaVIP</title>
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" />
</head>
<body>
    <div class="container">
        <div class="jumbotron" align="center" style="margin-top: 50px;">
            <h1>Seja bem vindo ao ListaVIPs</h1>
            <div align="center">
                <a href="listavip" class="btn btn-lg btn-primary">Clique aqui para ver a lista de convidados</a>
            </div>
        </div>
    </div>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
</body>
</html>

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>br.gabrieelmoura.listavip</groupId>
    <artifactId>listavip</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>1.4.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
            <version>1.4.1.RELEASE</version>
        </dependency>
    </dependencies>
</project>

Resposta retornada:

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Mon Feb 12 19:13:48 BRST 2018
There was an unexpected error (type=Not Found, status=404).
No message available