Merge pull request #136 from mengwong/ghc9

compiles with GHC 9.0.2

src/runtime/haskell-bind/pgf2.cabal

@@ -26,7 +26,7 @@ library
     PGF2.Expr,
     PGF2.Type
   build-depends:
-    base >= 4.9.1 && < 4.15,
+    base >= 4.9.1 && < 4.16,
     containers >= 0.5.7 && < 0.7,
     pretty >= 1.1.3 && < 1.2
   default-language: Haskell2010

src/runtime/haskell/pgf.cabal

@@ -15,7 +15,7 @@ library
   default-language: Haskell2010
   build-depends:
     array >= 0.5.1 && < 0.6,
-    base >= 4.9.1 && < 4.15,
+    base >= 4.9.1 && < 4.16,
     bytestring >= 0.10.8 && < 0.11,
     containers >= 0.5.7 && < 0.7,
     ghc-prim >= 0.5.0 && < 0.7,