Allow transformers 0.6.

Author: jgm

changelog

@@ -10,6 +10,8 @@
 
   * Allow aeson 2+.  Tested with aeson 2.0.1.0.
 
+  * Allow transformers 0.6.
+
   * Fix incorrect table ColWidth documentation (#85, Nils Carlson).
     The documentation stated that the ColWidth represented the width
     of the column as a fraction of the table width when in represents

pandoc-types.cabal

@@ -57,7 +57,7 @@ Library
                      ghc-prim >= 0.2,
                      bytestring >= 0.9 && < 0.12,
                      aeson >= 0.6.2 && < 2.1,
-                     transformers >= 0.2 && < 0.6,
+                     transformers >= 0.2 && < 0.7,
                      QuickCheck >= 2.10 && < 2.15
   if !impl(ghc >= 8.0)
     Build-depends:   semigroups == 0.18.*