fix: Ensure readme image is updated and works.

Makefile

@@ -19,3 +19,7 @@ lint:
 format:
  ruff --fix src tests
  black src tests
+
+readme-image:
+ FORCE_COLOR=true python readme.py --help | ansitoimg --title '' docs/source/_static/example.svg
+

README.md

@@ -14,31 +14,30 @@ inspiration from the "Derive" API from the
 [Clap](https://docs.rs/clap/latest/clap/_derive/index.html) written in Rust.
 
 ```python
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 import cappa
+from typing import Literal
 from typing_extensions import Annotated
 
 
 @dataclass
 class Example:
- positional_arg: str
- boolean_flag: bool
- single_option: Annotated[
- int | None,
- cappa.Arg(short=True, long=True, help="consectetur adipiscing elit"),
- ]
+ positional_arg: str = "optional"
+ boolean_flag: bool = False
+ single_option: Annotated[int | None, cappa.Arg(short=True, help="A number")] = None
  multiple_option: Annotated[
  list[Literal["one", "two", "three"]],
- cappa.Arg(short=True, long=True, help="Lorem ipsum dolor sit amet"),
- ]
+ cappa.Arg(long=True, help="Pick one!"),
+ ] = field(default_factory=list)
 
 
 args: Example = cappa.parse(Example, backend=cappa.backend)
+print(args)
 ```
 
 Produces the following CLI:
 
-![help text](./docs/source/_static/example.png)
+![help text](./docs/source/_static/example.svg)
 
 In this way, you can turn any dataclass-like object (with some additional
 annotations, depending on what you're looking for) into a CLI.