[BCI-3438] Add stub chain writer method onto starknet relayer (#475)

* starknet: Add stub method onto starknet relayer

* starknet: Add ctx into NewChainWriter method

* starket: Reset go mods

* starknet: Fix return type of chain writer constructor

---------

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

relayer/pkg/chainlink/relay.go

@@ -55,6 +55,10 @@ func (r *relayer) HealthReport() map[string]error {
 	return map[string]error{r.Name(): r.Healthy()}
 }
 
+func (r *relayer) NewChainWriter(_ context.Context, _ []byte) (relaytypes.ChainWriter, error) {
+	return nil, errors.New("chain writer is not supported for starknet")
+}
+
 func (r *relayer) NewContractReader(_ []byte) (relaytypes.ContractReader, error) {
 	return nil, errors.New("contract reader is not supported for starknet")
 }