chore: update gen2-migration guide

[dgandhi62]

Changes

1. userAttributes are supported. They can be seen amplify/auth/resource.ts

import { defineAuth } from '@aws-amplify/backend';
import { testingapp1e98cb604e98cb604DefineAuthChallenge } from './testingapp1e98cb604e98cb604DefineAuthChallenge/resource';
import { testingapp1e98cb604e98cb604CreateAuthChallenge } from './testingapp1e98cb604e98cb604CreateAuthChallenge/resource';
import { testingapp1e98cb604e98cb604VerifyAuthChallengeResponse } from './testingapp1e98cb604e98cb604VerifyAuthChallengeResponse/resource';
import { testingapp1e98cb604e98cb604CustomMessage } from './testingapp1e98cb604e98cb604CustomMessage/resource';
import { testingapp1e98cb604e98cb604PreSignup } from './testingapp1e98cb604e98cb604PreSignup/resource';
import { testingapp1e98cb604e98cb604PreTokenGeneration } from './testingapp1e98cb604e98cb604PreTokenGeneration/resource';

export const auth = defineAuth({
  loginWith: {
    email: true,
  },
  userAttributes: {
    profilePage: {
      required: true,
      mutable: true,
    },
    address: {
      required: true,
      mutable: true,
    },
    birthdate: {
      required: true,
      mutable: true,
    },
    gender: {
      required: true,
      mutable: true,
    },
    preferredUsername: {
      required: true,
      mutable: true,
    },
    lastUpdateTime: {
      required: true,
      mutable: true,
    },
    website: {
      required: true,
      mutable: true,
    },
    profilePicture: {
      required: true,
      mutable: true,
    },
    phoneNumber: {
      required: true,
      mutable: true,
    },
    timezone: {
      required: true,
      mutable: true,
    },
    locale: {
      required: true,
      mutable: true,
    },
    givenName: {
      required: true,
      mutable: true,
    },
    familyName: {
      required: true,
      mutable: true,
    },
    middleName: {
      required: true,
      mutable: true,
    },
    fullname: {
      required: true,
      mutable: true,
    },
    nickname: {
      required: true,
      mutable: true,
    },
  },
  triggers: {
    defineAuthChallenge: testingapp1e98cb604e98cb604DefineAuthChallenge,
    createAuthChallenge: testingapp1e98cb604e98cb604CreateAuthChallenge,
    verifyAuthChallengeResponse:
      testingapp1e98cb604e98cb604VerifyAuthChallengeResponse,
    customMessage: testingapp1e98cb604e98cb604CustomMessage,
    preSignUp: testingapp1e98cb604e98cb604PreSignup,
    preTokenGeneration: testingapp1e98cb604e98cb604PreTokenGeneration,
  },
  multifactor: {
    mode: 'OFF',
  },
});

2. Email Domain Filtering (denylist) should be supported along with allowlist. The evidence for the following is below:

In Gen1, both capabilities are defined here. Denylist maps to PreSignup: ['email-filter-denylist'] and allowlist maps to PreSignup: ['email-filter-allowlist']. Both are just PreSignup Lambda triggers with different template scaffolding.

The migration tool handles both identically through the generic trigger path. The mapping is made here. The migration tool has no awareness of whether the PreSignup trigger is an allowlist or denylist.

Sample output

triggers: {
    defineAuthChallenge: testingapp1e98cb604e98cb604DefineAuthChallenge,
    createAuthChallenge: testingapp1e98cb604e98cb604CreateAuthChallenge,
    verifyAuthChallengeResponse:
      testingapp1e98cb604e98cb604VerifyAuthChallengeResponse,
    customMessage: testingapp1e98cb604e98cb604CustomMessage,
    preSignUp: testingapp1e98cb604e98cb604PreSignup,
    preTokenGeneration: testingapp1e98cb604e98cb604PreTokenGeneration,
  },

While we don't know if further handling is needed for the other triggers, denylist should be supported.

3. lambda triggers for dynamodb tables are supported as seen here

4. cognito lambda triggers should be supported as seen here