glgen: Allow building with filepath-1.5.*

glgen.cabal

@@ -54,7 +54,7 @@ executable glgen
   build-depends:
     base == 4.*,
     directory >= 1.2 && <= 1.4,
-    filepath >= 1.3 && < 1.5,
+    filepath >= 1.3 && < 1.6,
     hxt == 9.3.*,
     transformers >= 0.2 && < 0.7,
     containers >= 0.5 && < 0.8