Update CLDR version mentioned in README.

Reorder VE regions, rename VE-A.

Update to CLDR v45. No data changes.

Add a locality field to the format for Singapore (SG).

Source: https://www.upu.int/UPU/media/upu/PostalEntitiesFiles/addressingUnit/sgpEn.pdf

Rebuld the address format for Kazakhstan, add regions.

Fix CheckPostalCode to Validate Input Strictly (#3)

* Fix CheckPostalCode to only pass valid inputs

* Reject non-empty postal codes if not required

Add regions for Seychelles (SC) and Paraguay (PY).

Update to CLDR v43.

Further optimize RegionMap.MarshalJSON().

- Stop calling the encoder for values as well.
- Use tests to ensure that regions always contain valid utf8.

Allocations are now down 80% in FormatHandler.

Update to CLDR v42. No data changes.