session-info: add new fields + migration (#4545)

* session_info: v2 + migration

* use primitives::v2

* use polkadot_primitives::v2

* impl primitives::v2

* fix approval-voting tests

* fix other tests

* hook storage migration up

* backwards compat (1)

* backwards compat (2)

* fmt

* fix tests

* FMT

* do not reexport v1 in v2

* fmt

* set storage version to 1

Co-authored-by: Javier Viola <javier@parity.io>

polkadot/node/subsystem-util/src/rolling_session_window.rs

@@ -20,7 +20,10 @@
 //! care about the state of particular blocks.
 
 pub use polkadot_node_primitives::{new_session_window_size, SessionWindowSize};
-use polkadot_primitives::v1::{Hash, SessionIndex, SessionInfo};
+use polkadot_primitives::{
+	v1::{Hash, SessionIndex},
+	v2::SessionInfo,
+};
 
 use futures::channel::oneshot;
 use polkadot_node_subsystem::{
@@ -288,6 +291,7 @@ mod tests {
 			n_delay_tranches: index as _,
 			no_show_slots: index as _,
 			needed_approvals: index as _,
+			active_validator_indices: Vec::new(),
 		}
 	}