v3.1.2

Fix github actions

v3.1.0

Make sure Zip4 returns a string instead of an object

Rewrite

This is a library rewrite from the original madison-reed source.

Breaking changes

• Now uses USPS terminology.
  street1 => Address1
  street2 => Address2
  For all others, see the .d.ts files.

Internal changes

• Use standard error type
• Split class into modules