Add belated changelog entry for #5351 [skip ci]

cc @mpickering

Author: hvr

cabal-install/changelog

@@ -50,6 +50,9 @@
 	* Default changelog generated by 'cabal init' is now named
 	  'CHANGELOG.md' (#5441).
 	* Align output of 'new-build' command phases (#4040).
+	* Add suport for specifying remote VCS dependencies via new
+	  'source-repository-package' stanzas in 'cabal.project' files
+	  (#5351).
 
 2.2.0.0 Mikhail Glushenkov <[email protected]> March 2018
 	* '--with-PROG' and '--PROG-options' are applied to all packages