feat: Forwards-compatible getRelayDataHash() (#852)

Promoting address (bytes20) -> bytes32 and uint32 -> uint256 produces
identical RelayData hashes. This is verified by the existing tests
passing (they are verified against the existing SpokePool deployments
with address and uint32 in RelayData).

Author: pxrl

src/utils/SpokeUtils.ts

@@ -222,26 +222,34 @@ export async function getDepositIdAtBlock(contract: Contract, blockTag: number):
  * @returns The corresponding RelayData hash.
  */
 export function getRelayDataHash(relayData: RelayData, destinationChainId: number): string {
+  const _relayData = {
+    ...relayData,
+    depositor: ethersUtils.hexZeroPad(relayData.depositor, 32),
+    recipient: ethersUtils.hexZeroPad(relayData.recipient, 32),
+    inputToken: ethersUtils.hexZeroPad(relayData.inputToken, 32),
+    outputToken: ethersUtils.hexZeroPad(relayData.outputToken, 32),
+    exclusiveRelayer: ethersUtils.hexZeroPad(relayData.exclusiveRelayer, 32),
+  };
   return ethersUtils.keccak256(
     ethersUtils.defaultAbiCoder.encode(
       [
         "tuple(" +
-          "address depositor," +
-          "address recipient," +
-          "address exclusiveRelayer," +
-          "address inputToken," +
-          "address outputToken," +
+          "bytes32 depositor," +
+          "bytes32 recipient," +
+          "bytes32 exclusiveRelayer," +
+          "bytes32 inputToken," +
+          "bytes32 outputToken," +
           "uint256 inputAmount," +
           "uint256 outputAmount," +
           "uint256 originChainId," +
-          "uint32 depositId," +
+          "uint256 depositId," +
           "uint32 fillDeadline," +
           "uint32 exclusivityDeadline," +
           "bytes message" +
           ")",
         "uint256 destinationChainId",
       ],
-      [relayData, destinationChainId]
+      [_relayData, destinationChainId]
     )
   );
 }