v3.9.0 Country subdivisions have been added

What's Changed

• Implement country subdivisions by @PrinsFrank in #230
• Add relation between country and subdivision by @PrinsFrank in #236
• Add relationship between countrySubdivision and identical country by @PrinsFrank in #237
• Add documentation for country subdivisions by @PrinsFrank in #238
• Add relation to parent/child countries now that we have this information in subdivisions by @PrinsFrank in #239

Other changes

• Fix url in CurrencyAlpha3 by @szepeviktor in #233
• Sorting should be configurable per enum file instead of per enum mapping as one mapping can result in multiple enum files by @PrinsFrank in #231
• Fix automatic country code generation being flakey when javascript is not fully loaded yet by @PrinsFrank in #243
• Fix enum method generation issues with docblocks by @PrinsFrank in #241

Full Changelog: v3.8.8...v3.9.0