Maven, Wrong class version for adding dependency

Question

I'm trying to add the dependency Mythic-Dist to my maven project but this one uses 60 as class version. My jdk version is 8 and language level is also 8. At the moment I have this message :

(Can't process class [io/lumine/mythic/core/Joshinn.class] (Unsupported class version number [60.0] (maximum 52.0, Java 1.8)))

I'm also using proguard and as far as I know, it cannot be used with another jdk so I don't know how to treat that. I'm not a maven expert at all so I may be doing something wrong.

This is my pom :

<?xml version="1.0" encoding="UTF-8"?>
<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.civious.dungeonmmo</groupId>
    <artifactId>DungeonMMO</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <build>
        <defaultGoal>clean package</defaultGoal>

        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.0</version>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.6</version>
                <configuration>
                    <jarName>DungeonMMO</jarName>
                </configuration>
            </plugin>

            <plugin>
                <groupId>com.github.wvengen</groupId>
                <artifactId>proguard-maven-plugin</artifactId>
                <version>2.0.13</version>
                <executions>
                    <execution>
                        <id>obfuscation-packaging</id>
                        <phase>package</phase>
                        <goals>
                            <goal>proguard</goal>
                        </goals>
                        <configuration>
                            <injar>DungeonMMO.jar</injar>
                            <obfuscate>true</obfuscate>
                            <attach>true</attach>
                            <appendClassifier>false</appendClassifier>
                            <addMavenDescriptor>true</addMavenDescriptor>
                            <libs>
                                <lib>${java.home}/lib/rt.jar</lib>
                            </libs>

                            <options>
                                <option>-dontshrink</option>
                                <option>-dontoptimize</option>
                                <option>-dontnote **</option>
                                <option>-dontwarn **</option>
                                <option>-target 1.8</option>
                                <!-- Keeping Main class -->
                                <option>-keep class
                                    com.civious.dungeonmmo.DungeonMMO
                                </option>
                                <option>-keepclassmembers class * extends java.lang.Enum {
                                    <![CDATA[<fields>]]>;
                                    public static **[] values();
                                    public static ** valueOf(java.lang.String);
                                    }
                                </option>
                                <option>-keepattributes !LocalVariableTable,!LocalVariableTypeTable</option>
                            </options>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spigot-repo</id>
            <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
        </repository>

        <repository>
            <id>bungeecord-repo</id>
            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
        </repository>

        <repository>
            <id>Multiverse-Core</id>
            <url>https://repo.onarandombox.com/content/repositories/multiverse/</url>
        </repository>

        <repository>
            <id>nexus</id>
            <name>Lumine Releases</name>
            <url>https://mvn.lumine.io/repository/maven-public/</url>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>com.onarandombox.multiversecore</groupId>
            <artifactId>Multiverse-Core</artifactId>
            <version>4.3.1</version>
            <exclusions>
                <exclusion>
                    <groupId>org.bukkit</groupId>
                    <artifactId>bukkit</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.bukkit</groupId>
                    <artifactId>craftbukkit</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.spigotmc</groupId>
            <artifactId>spigot-api</artifactId>
            <version>1.17-R0.1-SNAPSHOT</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.5.Final</version>
        </dependency>

        <dependency>
            <groupId>io.lumine</groupId>
            <artifactId>Mythic-Dist</artifactId>
            <version>5.0.3-SNAPSHOT</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>

</project>

Thanks for your help.