Update CHANGELOG.md

[davidme-stripe]

• Ensure the CHANGELOG is up to date with all relevant commits since the last release
• Add the version number for this release & the date to the CHANGELOG, underneath "## Unreleased"
  • e.g. "## 1.2.3 - 2022-02-14"
• Update the README if necessary (this is only required when there are breaking changes in the release, such as dropping support for an iOS || Android version)