Add EIP number

Author: axic

EIPS/eip-draft_reduced_gas_cost_for_call_to_self.md

@@ -1,5 +1,5 @@
 ---
-eip: <to be assigned>
+eip: 1380
 title: Reduced gas cost for call to self
 author: Alex Beregszaszi (@axic), , Jacques Wagener (jacqueswww)
 discussions-to: <TBA>