Release 4.3.7

What's Changed

• Adds staging ENV support for the sample app by @stefan-tudor in #271
• Prefixes and cleans up the SDK strings by @RafalOzogJudopay in #270
• Refactors Ravelin tests by @eugenezhernakov in #272
• Includes tablet as a target in UI testing by @eugenezhernakov in #273
• Adds iDEAL UI tests by @eugenezhernakov in #275
• Updates API version to 6.21 by @RafalOzogJudopay in #276
• Add tests for the primary account details feature by @eugenezhernakov in #277
• Implements Indian and Chinese States/Provinces in billing info form by @RafalOzogJudopay in #279
• Bump up the package version by @stefan-tudor in #285

Full Changelog: v4.3.6...v4.3.7