Use latest commonmark, commonmark-extensions.

This fixes a bug with nested blocks in footnotes with the
`footnote` extension to `commonmark`.  See jgm/commonmark-hs#63.

pandoc.cabal

@@ -405,8 +405,8 @@ library
                  bytestring            >= 0.9      && < 0.12,
                  case-insensitive      >= 1.2      && < 1.3,
                  citeproc              >= 0.1.0.3  && < 0.2,
-                 commonmark            >= 0.1.0.2  && < 0.2,
-                 commonmark-extensions >= 0.2      && < 0.3,
+                 commonmark            >= 0.1.1    && < 0.2,
+                 commonmark-extensions >= 0.2.0.2  && < 0.3,
                  commonmark-pandoc     >= 0.2      && < 0.3,
                  connection            >= 0.3.1,
                  containers            >= 0.4.2.1  && < 0.7,

stack.yaml

@@ -19,8 +19,8 @@ extra-deps:
 - HsYAML-0.2.1.0
 - HsYAML-aeson-0.2.0.0
 - doctemplates-0.8.2
-- commonmark-0.1.0.2
-- commonmark-extensions-0.2.0.1
+- commonmark-0.1.1
+- commonmark-extensions-0.2.0.2
 - commonmark-pandoc-0.2.0.1
 - git: https://github.com/jgm/citeproc
   commit: 1860f189e9995c1dc27a68893bedfbf8de1ee67f