dynamodb global secondary indexes

[Fejuto]

Describe the bug
error:
C:\Users\Fejuto\Documents\git\idlegame\cdk\node_modules@aws-cdk\aws-dynamodb\lib\table.ts:259
throw new RangeError('a maximum number of global secondary index per table is 5');

limit for global secondary indexes is actually 20 https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html#limits-secondary-indexes

To Reproduce
make dynamodb table and add more than 5 global secondary indexes

[eladb]

Thanks for reporting