Failed to execute goal on project paperspigot: Could not resolve dependencies for project org.github.paperspigot:paperspigot:jar:1.8.8-R0.1-SNAPSHOT: Failed to collect dependencies at org.spigotmc:minecraft-server:jar:1.8.8-SNAPSHOT: Failed to read artifact descriptor for org.spigotmc:minecraft-server:jar:1.8.8-SNAPSHOT: Could not transfer artifact org.spigotmc:minecraft-server:pom:1.8.8-SNAPSHOT from/to md_5-releases (http://repo.md-5.net/content/repositories/releases/): Failed to transfer file: http://repo.md-5.net/content/repositories/releases/org/spigotmc/minecraft-server/1.8.8-SNAPSHOT/minecraft-server-1.8.8-SNAPSHOT.pom. Return code is: 400 , ReasonPhrase:Repository version policy: RELEASE does not allow version: 1.8.8-SNAPSHOT. -> [Help 1]

To see the full stack trace of the errors, re-run Maven with the -e switch.
Re-run Maven using the -X switch to enable full debug logging.