0.7.51

SAM Policy document (#3)

* add json decoder

* decode statements

* implement root template decoder

* add mkJson* functions

* convert policy template to valid json

* use pretty render

* gen sam policy-template

* refactor to use JSON.dhall

* mk package.dhall

* refactor:move sam module;remove union type for CfnText

* update readme dhall

* fix unit test

* bump version

* freeze JSON sha

* fix dhall version

* use nix to package

* upload cache