Simplify deposit_event declaration in decl_module (#3506)

* simplify module deposit_event declaration

* fix

* bump version

* fix

* fix test

* fix doc

substrate/srml/treasury/src/lib.rs

@@ -139,7 +139,7 @@ decl_module! {
 		/// Percentage of spare funds (if any) that are burnt per spend period.
 		const Burn: Permill = T::Burn::get();
 
-		fn deposit_event<T>() = default;
+		fn deposit_event() = default;
 		/// Put forward a suggestion for spending. A deposit proportional to the value
 		/// is reserved and slashed if the proposal is rejected. It is returned once the
 		/// proposal is awarded.