chore: update default testnet to sepolia

serverless.yml

@@ -150,7 +150,7 @@ custom:
     autoDomain: true
   KMS_ARN: ${env:KMS_ARN, "PLACEHOLDER_ARN"}
   ethereumConfig:
-    stg: "goerli"
+    stg: "sepolia"
     production: "homestead"
   ssm:
     # reason why some variable is empty because in sls3 it throw error if the variable does not exist

src/config.ts

@@ -82,7 +82,7 @@ const generateConfig = () => ({
   euSigner: getEuSigner(),
   gpaySigner: getGPayCovidCardSigner(),
   env: process.env.NODE_ENV,
-  network: getDefaultIfUndefined(process.env.ETHEREUM_NETWORK, "goerli"),
+  network: getDefaultIfUndefined(process.env.ETHEREUM_NETWORK, "sepolia"),
   isValidationEnabled: !(
     process.env.IS_OFFLINE || process.env.IDENTIFIER_VALIDATION === "false"
   ),