Fix crash when attack speed doesnt exist

Fixes #179

Author: Shnupbups

src/main/java/com/github/chainmailstudios/astromine/mixin/MiningToolItemMixin.java

@@ -33,6 +33,7 @@
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
 
+import java.util.Optional;
 import java.util.UUID;
 
 @Mixin(MiningToolItem.class)
@@ -42,6 +43,7 @@ public abstract class MiningToolItemMixin implements MiningToolItemAccess {
 
 	@Override
 	public double astromine_getAttackSpeed() {
-		return getAttributeModifiers(EquipmentSlot.MAINHAND).get(EntityAttributes.GENERIC_ATTACK_SPEED).stream().filter((EntityAttributeModifier modifier) -> modifier.getId().equals(UUID.fromString("FA233E1C-4180-4865-B01B-BCCE9785ACA3"))).findFirst().get().getValue();
+		Optional<EntityAttributeModifier> opt = getAttributeModifiers(EquipmentSlot.MAINHAND).get(EntityAttributes.GENERIC_ATTACK_SPEED).stream().filter((EntityAttributeModifier modifier) -> modifier.getId().equals(UUID.fromString("FA233E1C-4180-4865-B01B-BCCE9785ACA3"))).findFirst();
+		return opt.map(EntityAttributeModifier::getValue).orElse(0d);
 	}
 }