prepare changelog to update to 0.3.0

CHANGELOG.md

@@ -5,13 +5,22 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+Nothing
+
+## [0.3.0] - 2020-07-03
 ### Changed
  - The description in `Cargo.toml` was changed to from "The teloxide's macros for internal usage" to "The teloxide's procedural macros".
+ - Now parsing of arguments happens using special function. There are 3 possible variants:
+   - Using `default` parser, which only put all text in one String field.
+   - Using `split` parser, which split all text by `separator` (by default is whitespace) and then use FromStr::from_str to construct value.
+   - Using custom separator.
+ - Now function `parse` return Result<T, ParseError> instead of Option<T>.
 
 ### Added
  - This `CHANGELOG.md`.
  - `.gitignore`.
-
+ - `#[parse_with]` attribute.
+ - `#[separator='%sep%']` attribute.
 
 ## [0.1.2] - 2020-02-24
 ### Changed