Added signing plugin

worldedit-sponge/build.gradle

@@ -8,6 +8,7 @@ buildscript {
 }
 
 plugins {
+    id 'signing'
     id 'org.spongepowered.plugin' version '0.8.1'
 }
 
@@ -42,3 +43,8 @@ shadowJar {
 artifacts {
     archives shadowJar
 }
+
+signing {
+    required false
+    sign shadowJar
+}