relax dependency versions

walint.cabal

@@ -34,7 +34,7 @@ library
         Util
         Types
         Paths
-    build-depends:    base ^>=4.14.1.0,
+    build-depends:    base,
                       aeson,
                       bytestring,
                       containers,
@@ -52,7 +52,7 @@ library
 executable walint
     main-is:          Main.hs
     ghc-options: -Wall
-    build-depends:    base ^>=4.14.1.0,
+    build-depends:    base,
                       walint,
                       getopt-generics,
                       aeson,