Bump version to 0.7.2.3.

Changelog

+Changed in version 0.7.2.3:
+   * Fix hsc2hs-related warning on ghc-8
+   * Fix the behavior of ctrl-W in the emacs bindings
+   * Point to github instead of trac
+
 Changed in version 0.7.2.2:
    * Fix Linux to Windows cross-compile
    * Canonicalize AMP instances to make the code more future proof

haskeline.cabal

 Name:           haskeline
 Cabal-Version:  >=1.10
-Version:        0.7.2.2
+Version:        0.7.2.3
 Category:       User Interfaces
 License:        BSD3
 License-File:   LICENSE