Remove prerelase info from the CHANGELOG

Author: nex3

CHANGELOG.md

@@ -1,44 +1,3 @@
-## 1.0.0-beta.2
+## 1.0.0
 
-* No user-visible changes.
-
-## 1.0.0-beta.1
-
-* Too many changes to list.
-
-## 1.0.0-alpha.5
-
-* **Breaking change**: Remove `lib/runner.dart`. This package is only meant to
-  be used as an executable, not as a library.
-
-* **Breaking change**: Remove the option to negate the `--migrate-deps`,
-  `--dry-run`, and `--verbose` flags.
-
-* Expose `sass-migrator` as a globally-installable executable.
-
-### Division Migrator
-
-* Fix a type error.
-
-### Module Migrator
-
-* Convert removed color functions to `color.adjust()`.
-
-## 1.0.0-alpha.4
-
-* Internal changes only.
-
-## 1.0.0-alpha.3
-
-* Division migrator: Treat most slash operations within argument lists as
-  division.
-* Division migrator: Only migrate slash operations to slash-list calls in a
-  non-plain-CSS context.
-
-## 1.0.0-alpha.2
-
-* Internal changes only.
-
-## 1.0.0-alpha.1
-
-* Initial alpha release.
+* Initial release.