Amplify buildspec with fix for https://github.com/aws-amplify/amplify-cli/issues/8392

amplify.yml

version: 1
backend:
  phases:
    build:
      commands:
        - |-
          export X=`npm root -g`
          cd $X/@aws-amplify/cli/node_modules/amplify-provider-awscloudformation && npm install ajv@^6.12.3
        - amplifyPush --simple
frontend:
  phases:
    preBuild:
      commands:
        - nvm install 14
        - npm ci
        - npm install --silent --global expo-cli
        - |-
          if [ -f yarn.lock ]; then
           yarn
          elif [ -f package-lock.json ] || [ -f npm-shrinkwrap.json ]; then
           npm ci
          else
           npm install
          fi
    build:
      commands:
        - "expo build:web"
  artifacts:
    baseDirectory: web-build
    files:
      - "**/*"
  cache:
    paths:
      - node_modules/**/*
      - $(npm root --global)/**/*