Add CHANGELOG.md

Document all changes since v0.6, grouped by category:
breaking changes, additions, fixes, and maintenance.

Author: lavr

CHANGELOG.md

@@ -0,0 +1,38 @@
+# Changelog
+
+## Unreleased
+
+### Breaking changes
+
+- Dropped Python 2 support. Python 3.9+ is now required (#188)
+- HTML transformation dependencies (`cssutils`, `lxml`, `chardet`, `requests`, `premailer`) are now optional — install with `pip install emails[html]` (#190)
+
+### Added
+
+- Python 3.13 and 3.14 support (#184)
+- CC/BCC importing in MsgLoader (#182)
+- RFC 6532 support — non-ASCII characters in email addresses (#138)
+- In-memory SMTP backend (#136)
+- SMTP integration tests using Mailpit (#186)
+
+### Fixed
+
+- SMTP connection is now properly closed on any initialization failure (#180)
+- SMTP connection is now properly closed on failed login (#173)
+- Incorrect `isinstance` check in `parse_name_and_email_list` (#176)
+- Message encoding to bytes in SMTP backend (#152)
+- Unique filename generation for attachments
+- Regex escape sequence warning (#148)
+- Replaced deprecated `cgi` module with `email.message`
+
+### Maintenance
+
+- Updated pre-commit hooks to current versions
+- Updated GitHub Actions to supported versions
+- Removed universal wheel flag (py3-only)
+- Cleaned up documentation and project metadata
+- Added Python 3.12 to test matrix (#169)
+
+## 0.6 — 2019-07-14
+
+Last release before the changelog was introduced.