Maven compilation error: Module not found: junit

I'm getting the following error messages when I try to run a simple project with maven, java modules and junit 5:

 Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project echo: Compilation failure: Compilation failure:
[ERROR] /C:/Users/andre/eclipse-workspace/echo/src/main/java/module-info.java:[2,35] module not found: org.junit.jupiter.engine
[ERROR] /C:/Users/andre/eclipse-workspace/echo/src/main/java/module-info.java:[3,35] module not found: org.junit.jupiter.api
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

This is my directory structure:

echo
----src/main/java
--------com.udp.echo
------------App.java
------------EchoClient.java
------------EchoServer.java
--------module-info.java
----src/test/java/com.udp.echo
--------EchoTest.java
----pom.xml

this is my module-info.java file:

open module echo {
    requires junit;
}

I actually tried to do require org.junit.jupiter.api and require org.junit.jupiter.engine but this won't change the outcome.

this is my 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>com.udp</groupId>
    <artifactId>echo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>echo</name>
    <url>http://maven.apache.org</url>

    <properties>
        <java.version>12</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <maven.compiler.source>12</maven.compiler.source>
        <maven.compiler.target>12</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>5.4.2</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <version>5.4.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.1</version>
                </plugin>
            </plugins>
        </pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.22.0</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-failsafe-plugin</artifactId>
                <version>2.22.0</version>
            </plugin>
        </plugins>
    </build>
</project>

this is the result of running mvn -v:

$ mvn -v
Apache Maven 3.6.1 (d66c9c0b3152b2e69ee9bac180bb8fcc8e6af555; 2019-04-04T16:00:29-03:00)
Maven home: C:\apache-maven-3.6.1
Java version: 12.0.1, vendor: Oracle Corporation, runtime: C:\java\jdk-12.0.1
Default locale: pt_BR, platform encoding: Cp1252
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"

Wasn't maven supposed to download it's dependencies from the maven repository? If so, why is it complaining about a module not being found? This just makes no sense to me.

What am I missing?