Update JUnit 5 documentation for simpler configuration

[mikomatic]

Hello everyone, thanks for the useful framework.

While setting this up with Junit 5, I noticed documentation can be updated, with a slightly simpler configuration:

• By upgrading to maven-surefire-plugin to 2.22.2, one does not need to provided a junit-platform-surefire-provider anymore (it is deprecated on latests version of Junit 5)
• When using the latest version of allure-maven (2.10.0), it is not necessary to provide reportVersion in the configuration
• When using the latest version of allure-maven (2.10.0), it is not necessary to provide junit.jupiter.extensions.autodetection.enabled property.
• In order for the report to be generated via a mvn test allure:report, i had to customize allure.results.directory system property. (it is described somewhere else in the docs)

Below is my current setup

<properties>
    <aspectj.version>1.9.7</aspectj.version>
</properties>

<dependencies>
        <dependency>
            <groupId>io.qameta.allure</groupId>
            <artifactId>allure-junit5</artifactId>
            <version>LATEST_VERSION</version>
            <scope>test</scope>
        </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                 <version>2.22.2</version>
                <configuration>
                <testFailureIgnore>false</testFailureIgnore>
                        <argLine>
                            -javaagent:"${settings.localRepository}/org/aspectj/aspectjweaver/${aspectj.version}/aspectjweaver-${aspectj.version}.jar"
                        </argLine>
                    <systemProperties>
                       <allure.results.directory>${project.build.directory}/allure-results</allure.results.directory>
                    </systemProperties>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>org.aspectj</groupId>
                        <artifactId>aspectjweaver</artifactId>
                        <version>${aspectj.version}</version>
                    <dependency>
                </dependencies>
            </plugin>
            <plugin>
                <groupId>io.qameta.allure</groupId>
                <artifactId>allure-maven</artifactId>
                <version>LATEST_VERSION</version>
            </plugin>
    </plugins>
</build>
...

I'll gladly make a PR if you find these changes useful.

PS. Documentation seems exposed at two different URLs, what is the difference ?

• https://docs.qameta.io/allure-report/frameworks/java/junit5
• https://docs.qameta.io/allure/#_junit_5