Outgoing

-------------------
- Support python-dotenv v1.0
- Always read JSON configuration files using UTF-8 encoding
- Always read files for the "file" password method using UTF-8 encoding
- Support Python 3.12
- Correct the default Linux config file location listed in the README
- Update pydantic to v2.0

-------------------
- Update `platformdirs` dependency to v3. This is a **breaking** change on
macOS, where the default configuration path changes from
`~/Library/Preferences/outgoing/outgoing.toml` back to `~/Library/Application
Support/outgoing/outgoing.toml`.

-------------------
- Drop support for Python 3.6
- Support Python 3.11
- Use `tomllib` on Python 3.11

-------------------
- Overload `Password.__eq__` so that instances continue to compare equal to
`pydantic.SecretStr` instances even under pydantic 1.10

-------------------
- Support tomli 2.0

-------------------
- Support Python 3.10
- Replaced `entrypoints` dependency with `importlib-metadata`
- Replaced `appdirs` dependency with `platformdirs`. This is a **breaking**
change on macOS, where the default configuration path changes from
`~/Library/Application Support/outgoing/outgoing.toml` to
`~/Library/Preferences/outgoing/outgoing.toml`.