Specifying custom API key when used with usage plans

Hi - I am experiencing an issue when trying to specify an API key for private endpoints. Our API keys are linked to usage accounts and have been setup following https://www.serverless.com/framework/docs/providers/aws/events/apigateway#setting-api-keys-for-your-rest-api, under the "You can also setup multiple usage plans for your API. In this case you need to map your usage plans to your api keys. Here's an example how this might look like:" section.

Note this is working successfully as expected when deployed to AWS - the issue being experienced only occurs when running with serverless-offline.

Our application uses a serverless.ts file with various imports to separate out parts. So rather than reference the serverless.yml file I've put the results of the sls print command below.

I am currently using version 11.1.3 of serverless-offline.

Configuration

Results from sls print

service: ....
frameworkVersion: '3'
configValidationMode: error
plugins:
  - serverless-auto-swagger
  - serverless-esbuild
  - serverless-offline
  - serverless-iam-roles-per-function
provider:
  name: aws
  runtime: nodejs14.x
  region: eu-west-2
  profile: serverlessUser
  apiGateway:
    minimumCompressionSize: 1024
    shouldStartNameWithService: true
    apiKeys:
      - developmentPlan:
          - name: integration_test_key
            description: To be used for integration tests only
            value: API_KEY_VALUE_FOR_INTEGRATION_TESTS_TO_BE_USED_BY_SERVERLESS_OFFLINE
            enabled: true
      - productionPlan:
          - name: production_key
            description: To be used for production environment
            enabled: false
    usagePlan:
      - developmentPlan:
          quota:
            limit: 500
            period: DAY
          throttle:
            burstLimit: 200
            rateLimit: 20
      - productionPlan:
          quota:
            limit: 200
            period: WEEK
          throttle:
            burstLimit: 50
            rateLimit: 10
  environment:
    AWS_NODEJS_CONNECTION_REUSE_ENABLED: '1'
    NODE_OPTIONS: '--enable-source-maps --stack-trace-limit=1000'
  deploymentBucket: .....
  stage: dev
  versionFunctions: true
  deploymentBucketObject:
    ....
functions:
  ....
package:
  ...
resources:
  ...
custom:
  esbuild:
    bundle: true
    minify: false
    sourcemap: true
    exclude:
      - aws-sdk
    target: node14
    define: {}
    platform: node
    concurrency: 10
  ....
  serverless-offline:
    apiKey: iAmAKeyForIntegrationTestsAndShouldOnlyBeUsedForSuch

Behaviour

Running serverless offline shows that the API key being generated is a random value.

Offline [http for lambda] listening on http://localhost:3002
Function names exposed for local invocation by aws-sdk:
           .......
Remember to use 'x-api-key' on the request headers.
Key with token: 'd41d8cd98f00b204e9800998ecf8427e'

Desired behaviour is to have the the value API_KEY_VALUE_FOR_INTEGRATION_TESTS_TO_BE_USED_BY_SERVERLESS_OFFLINE used for the x-api-key header

Attempts

I have tried the --apiKey cli parameter as per documentation. However this appears to have been deprecated and is resulting in a

Error:
Detected unrecognized CLI options: "--apiKey".

I have also tried adding the override to the custom section of the serverless file

  custom: 
     serverless-offline:
        apiKey: API_KEY_VALUE_FOR_INTEGRATION_TESTS_TO_BE_USED_BY_SERVERLESS_OFFLINE

but still experience the random API key being used

dherault / serverless-offline