op-proposer: log L2OutputOracle version + address

Logs the L2OutputOracle version and address after building
a client to call it. This is generally useful information to
have and future implementations of the `op-proposer` will
need to function differently depending on the version to keep
the software compatible with both permissioned and permissionless
output proposal submission.

op-proposer/proposer/l2_output_submitter.go

@@ -208,6 +208,13 @@ func NewL2OutputSubmitter(cfg Config, l log.Logger) (*L2OutputSubmitter, error)
 		return nil, err
 	}
 
+	version, err := l2ooContract.Version(&bind.CallOpts{})
+	if err != nil {
+		cancel()
+		return nil, err
+	}
+	log.Info("Connected to L2OutputOracle", "address", cfg.L2OutputOracleAddr, "version", version)
+
 	parsed, err := abi.JSON(strings.NewReader(bindings.L2OutputOracleMetaData.ABI))
 	if err != nil {
 		cancel()