spec: update tags to v0.5.1

eth2/state_processing/src/per_epoch_processing/process_ejections.rs

@@ -4,7 +4,7 @@ use types::{BeaconStateError as Error, *};
 /// Iterate through the validator registry and eject active validators with balance below
 /// ``EJECTION_BALANCE``.
 ///
-/// Spec v0.5.0
+/// Spec v0.5.1
 pub fn process_ejections(state: &mut BeaconState, spec: &ChainSpec) -> Result<(), Error> {
     // There is an awkward double (triple?) loop here because we can't loop across the borrowed
     // active validator indices and mutate state in the one loop.