Protocol-Specification Version 1.2 release

### Description:

As part of the Protocol-Specification version 1.2 release, the following changes are targeted:

1. Create a schema called Document that can be attached to any Order, Item, or Fulfillment as an array of docs: https://github.com/beckn/protocol-specifications/issues/377
2. Need to add ItemQuantity to AddOns: https://github.com/beckn/protocol-specifications/issues/376
3. Need to add Document array in Order Schema to transmit order-related documents: https://github.com/beckn/protocol-specifications/issues/375
4. Required field 'return_reasons' in 'rating_categories' endpoint in meta.yaml ver 1.0.0: https://github.com/beckn/protocol-specifications/issues/355
5. "Errors in meta.yaml core ver 1.0.0": https://github.com/beckn/protocol-specifications/issues/354
6. "Errors in transaction.yaml core-v1.0.0": https://github.com/beckn/protocol-specifications/issues/350
7. Typo in readme file: https://github.com/beckn/protocol-specifications/issues/348
8. "ttl type inconsistent": https://github.com/beckn/protocol-specifications/issues/343

Other Issues which are fixed as part of this release but are not tracked using tickets.
1. Support & on_support Schema update
2. Price.value type changed to string from number
3. Xinput Schema Update
4. Payment Object schema update