bound the dependency versions

tahoe-capabilities.cabal

@@ -81,8 +81,8 @@ library
 
   -- Other library packages from which modules are imported.
   build-depends:
-    , base
-    , text
+    , base  >=4.7     && <5
+    , text  >=1.2.3.1 && <1.3
 
   -- Directories containing source files.
   hs-source-dirs:   src
@@ -114,5 +114,5 @@ test-suite tahoe-capabilities-test
 
   -- Test dependencies.
   build-depends:
-    , base
+    , base                >=4.7 && <5
     , tahoe-capabilities