Remove tested-with stanza from .cabal file

Author: saep

nvim-hs.cabal

@@ -30,7 +30,6 @@ copyright:           Copyright 2017 Sebastian Witte <[email protected]>
 category:            Editor
 build-type:          Simple
 cabal-version:       >=1.18
-tested-with:         GHC == 7.10.3, GHC == 8.0.2
 extra-source-files:    nvim-hs-devel.sh
                      , test-files/compile-error-for-quickfix-test1
                      , test-files/compile-error-for-quickfix-test2