Updated version for v.2.4.0 release of beacon-apis. (#294)

Author: rolfyone

beacon-node-oapi.yaml

@@ -21,7 +21,7 @@ info:
 
     Note that it is possible for a field to be added to an endpoint's data or metadata without an increase in the version number.
 
-  version: "Dev - Eth2Spec v1.1.0"
+  version: "v2.4.0 - Ethereum Proof-of-Stake Consensus Specification v1.3.0"
   contact:
     name: Ethereum Github
     url: https://github.com/ethereum/beacon-apis/issues