Version bump/ChangeLog modification

changelog.md

 # Changelog for [`process` package](http://hackage.haskell.org/package/process)
 
-## Unreleased changes
+## 1.6.5.1 *June 2019*
+
+* Version bound bumps
+* Slightly nicer error messages for internal errors
 
 ## 1.6.5.0 *December 2018*
 

process.cabal

 name:          process
-version:       1.6.5.0
+version:       1.6.5.1
 -- NOTE: Don't forget to update ./changelog.md
 license:       BSD3
 license-file:  LICENSE