compilation errror file name too long with very deep nested classes

```bash
codegenc ./APIs/openbanking.org.uk/account-info-openapi/3.1.7/openapi.yaml
codegen ./APIs/amazonaws.com/es/2015-01-01/openapi.yaml
```
gives

```
[ERROR] /tmp/client2615458670269948340/src/main/java/com/demo/api/schema/OBReadProduct2.java:[3435,77] error while writing com.demo.api.schema.OBReadProduct2.Data.Product.ProductItem.OtherProductType.LoanInterest.LoanInterestTierBandSet.LoanInterestTierBandSetItem.LoanInterestFeesCharges.LoanInterestFeesChargesItem.LoanInterestFeeChargeCap.LoanInterestFeeChargeCapItem.OtherFeeType.OtherFeeTypeItem.Builder: /tmp/client2615458670269948340/target/classes/com/demo/api/schema/OBReadProduct2$Data$Product$ProductItem$OtherProductType$LoanInterest$LoanInterestTierBandSet$LoanInterestTierBandSetItem$LoanInterestFeesCharges$LoanInterestFeesChargesItem$LoanInterestFeeChargeCap$LoanInterestFeeChargeCapItem$OtherFeeType$OtherFeeTypeItem$Builder.class: File name too long
```