ServerlessFramework stage毎にS3などのリソースを別に作る方法

provider > stage: ${opt:stage, self:custom.defaultStage}
custom > defaultStage: dev
custom > resourcePrefix : ${self:provider.stage}を使った値
と設定して
BucketNameを ${self:custom.resourcePrefix}-resourceとする

serverles.yml

service: serverless-sample

frameworkVersion: '2'

provider:
  name: aws
  runtime: python3.8
  stage: ${opt:stage, self:custom.defaultStage} 
  region: ${opt:provider, self:custom.defaultRegion}

custom:
  author: iwato
  defaultStage: dev
  defaultRegion: ap-northeast-1
  resourcePrefix: ${self:custom.author}-${self:service}-${self:provider.stage}
  environment:
    dev: ## 開発環境
      key: dev-value
    test: ## テスト環境
      key: test-value
    staging: ## 検証環境
      key: staging-value
    prod: ## 本番環境
      prod: prod-value

resources:
  Resources:
    NewResource:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${self:custom.resourcePrefix}-resource
  Outputs:
     NewOutput:
       Description: "Description for the output"
       Value: "Some output value"