Bump the base dep to >= 4.6.

We don't test with or support GHC 7.4.

Author: 23Skidoo

ekg-core.cabal

@@ -33,7 +33,7 @@ library
 
   build-depends:
     ghc-prim < 0.6,
-    base >= 4.5 && < 4.11,
+    base >= 4.6 && < 4.11,
     containers >= 0.5 && < 0.6,
     text < 1.3,
     unordered-containers < 0.3