Make timeout_height non-optional

packages/stargate/src/aminomsgs.ts

@@ -357,10 +357,12 @@ export interface AminoMsgTransfer extends AminoMsg {
     /** Bech32 account address */
     readonly receiver: string;
     /**
-     * It is unclear if this is really optional. The Amino encoding expects unset values to be
-     * encoded as {}.
+     * The timeout as a (revision_number, revision_height) pair.
+     *
+     * This fied is is non-optional (https://github.com/cosmos/cosmos-sdk/blob/v0.42.7/x/ibc/applications/transfer/types/tx.pb.go#L49).
+     * In order to not set the timeout height, set it to {}.
      */
-    readonly timeout_height?: AminoHeight;
+    readonly timeout_height: AminoHeight;
     /**
      * Timeout timestamp (in nanoseconds). The timeout is disabled when set to 0.
      *

packages/stargate/src/aminotypes.spec.ts

@@ -410,7 +410,7 @@ describe("AminoTypes", () => {
           token: coin(1234, "utest"),
           sender: "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6",
           receiver: "cosmos10dyr9899g6t0pelew4nvf4j5c3jcgv0r73qga5",
-          timeout_height: {}, // 🤷‍♂️
+          timeout_height: {},
           timeout_timestamp: undefined,
         },
       };