use gi-gtk3 and gi-gdk3 and bump stack to lts23

stack.yaml

@@ -1,7 +1,7 @@
 # For more information, see: http://docs.haskellstack.org/en/stable/yaml_configuration.html
 
 # Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
-resolver: lts-22.43
+resolver: lts-23.7
 
 # Local packages, usually specified by relative directory name
 packages:

stack.yaml.lock

@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    sha256: 08bd13ce621b41a8f5e51456b38d5b46d7783ce114a50ab604d6bbab0d002146
-    size: 720271
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/43.yaml
-  original: lts-22.43
+    sha256: 4ef79c30b9efcf07335cb3de532983a7ac4c5a4180bc17f6212a86b09ce2ff75
+    size: 680777
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/23/7.yaml
+  original: lts-23.7

termonad.cabal

@@ -88,11 +88,11 @@ library
                      , file-embed
                      , filepath
                      , focuslist
-                     , gi-gdk < 4
+                     , gi-gdk3
                      , gi-gdkpixbuf
                      , gi-gio
                      , gi-glib
-                     , gi-gtk >= 3.0.24 && < 4
+                     , gi-gtk3
                      , gi-pango
                      , gi-vte >= 2.91.19
                      , haskell-gi-base >= 0.21.2