Changelog for flock-0.2.3

0.2.3: * Add Erik Hesselink as maintainer. * Add CHANGELOG. 0.2.2: * Export the Lock type. 0.2.1: * Lock call no longer blocks other Haskell threads. 0.2: * Fixed build failure on GHC 6.12. * Added bounds on dependencies. 0.1: Initial release.