CREATE_FAILED: ApiGatewayMethodActionPost (AWS::ApiGateway::Method) - Invalid type for parameter selectionPattern #256

I'm trying to deploy my serverless app on local stack but Invalid type parameter for selectionPattern error is being thrown. Below is the complete error and serverless.yml

Error:

ApiGatewayMethodActionPost (Parameter validation failed:; Invalid type for parameter selectionPattern, value: 200, type: <class 'int'>, valid types: <class 'str'>)

serverless.yml

 events:
 - http:
 path: /action
 method: POST
 iamRole: arn:aws:iam::xxxxxxxxxxxx:role/someRole
 action: StartSyncExecution
 request:
 template:
 application/json: |
 {
 "stateMachineArn":"arn:aws:states:'us-west-2':xxxxxxxxxxxx:stateMachine:someMachine",
 "input": "$util.escapeJavaScript($input.json('$'))"
 }
 response:
 template: 
 application/json: |
 $input.path('$.output')

I was checking serverless-step-function code where selectionPattern is defined as integer and not string. Following is the link to the code: code