Replace config field with default value (srml/im-online) (#3388)

* Fix whitespacing

* Replace configurable fields with default values

* Bump version

* Apply suggestions from code review

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Fix more whitespacing

* Fix style

substrate/node/runtime/src/lib.rs

@@ -81,7 +81,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
 	spec_version: 140,
-	impl_version: 140,
+	impl_version: 141,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -436,7 +436,7 @@ construct_runtime!(
 		Treasury: treasury::{Module, Call, Storage, Event<T>},
 		Contracts: contracts,
 		Sudo: sudo,
-		ImOnline: im_online::{Module, Call, Storage, Event, ValidateUnsigned, Config<T>},
+		ImOnline: im_online::{Module, Call, Storage, Event, ValidateUnsigned, Config},
 	}
 );