Depend on dev version of pandoc-types.

(For aeson version bound.)

cabal.project

@@ -7,3 +7,7 @@ flags: +embed_data_files
 constraints: skylighting-format-blaze-html >= 0.1.1,
              skylighting-format-context >= 0.1.0.2
 
+source-repository-package
+  type: git
+  location: https://github.com/jgm/pandoc-types
+  tag: 2b68c905e75c65e66eaa4635e4c1bd6aabd6302f