Cosmos: Add support for the message handler (#971)

* Add Message handler

* Reorder types in the Cosmos manifest

Co-authored-by: Patrycja Zawadka <[email protected]>

Author: pienkowb

src/protocols/cosmos/manifest.graphql

@@ -42,10 +42,7 @@ type ContractMapping {
   blockHandlers: [BlockHandler!]
   eventHandlers: [EventHandler!]
   transactionHandlers: [TransactionHandler!]
-}
-
-type TransactionHandler {
-  handler: String!
+  messageHandlers: [MessageHandler!]
 }
 
 type BlockHandler {
@@ -64,6 +61,15 @@ type EventHandler {
   handler: String!
 }
 
+type TransactionHandler {
+  handler: String!
+}
+
+type MessageHandler {
+  message: String!
+  handler: String!
+}
+
 type Graft {
   base: String!
   block: BigInt!

src/protocols/cosmos/subgraph.js

@@ -16,6 +16,7 @@ module.exports = class CosmosSubgraph {
       'blockHandlers',
       'eventHandlers',
       'transactionHandlers',
+      'messageHandlers',
     ])
   }
 }