fix old releases dates
- Use getters to access `Span` fields (#1899).
-## [0.2.4] 2018-08-30
+## [0.2.4] 2017-08-30
### Added
- Add support for `Yield` (#1928).
-## [0.2.3] 2018-08-30
+## [0.2.3] 2017-08-30
### Added
