Ein Google Suche später:
Hier kannst du das auch nochmals nachlesen: https://www.spigotmc.org/wiki/spigot-maven/
<repositories>
<repository>
<id>spigot-repo</id>
<url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
</repository>
</repositories
<dependencies>
<dependency>
<groupId>org.spigotmc</groupId>
<artifactId>spigot-api</artifactId>
<version>1.8-R0.1-SNAPSHOT</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.bukkit</groupId>
<artifactId>bukkit</artifactId>
<version>1.8-R0.1-SNAPSHOT</version>
<scope>provided</scope>
</dependency>
</dependencies>