fix dialyzer

[KazuCocoa]

:0: Unknown function 'Elixir.JSX':decode/1
:0: Unknown function 'Elixir.JSX':'encode!'/1
:0: Unknown function 'Elixir.JSX':'prettify!'/1
lib/http_proxy/handle.ex:38: Invalid type specification for function 'Elixir.HttpProxy.Handle':start_link/1. The success typing is ([atom() | binary() | #{'port':=_, _=>_},...]) -> {'error',_} | {'ok',pid()}
lib/http_proxy/handle.ex:111: Invalid type specification for function 'Elixir.HttpProxy.Handle':schemes/0. The success typing is () -> ['http' | 'https',...]
lib/http_proxy/handle.ex:185: Function play_conn/1 has no local return
lib/http_proxy/handle.ex:195: Function no_match/1 will never be called
lib/http_proxy/handle.ex:200: Function 'matched_path?'/2 will never be called
lib/http_proxy/handle.ex:222: Function gen_response/2 will never be called
lib/http_proxy/play/paths.ex:24: The contract 'Elixir.HttpProxy.Play.Paths':paths() -> paths() cannot be right because the inferred return for paths() on line 29 is binary()
lib/http_proxy/play/paths.ex:24: The contract 'Elixir.HttpProxy.Play.Paths':paths() -> paths() cannot be right because the inferred return for paths() on line 60 is binary()
lib/http_proxy/play/paths.ex:45: The contract 'Elixir.HttpProxy.Play.Paths':path_patterns() -> paths() cannot be right because the inferred return for path_patterns() on line 50 is binary()
lib/http_proxy/play/paths.ex:45: The contract 'Elixir.HttpProxy.Play.Paths':path_patterns() -> paths() cannot be right because the inferred return for path_patterns() on line 71 is binary()
lib/http_proxy/play/paths.ex:59: Function 'path?'/1 has no local return
lib/http_proxy/play/paths.ex:70: Function 'path_pattern?'/1 has no local return
lib/http_proxy/play/paths.ex:71: The created fun has no local return
lib/http_proxy/play/response.ex:41: The created fun has no local return
lib/http_proxy/play/response.ex:42: The call 'Elixir.HttpProxy.Play.Response':validate(binary()) will never return since it differs in the 1st argument from the success typing arguments: (map())
lib/http_proxy/play/response.ex:48: Function gen_key/1 will never be called
lib/http_proxy/play/response.ex:68: Invalid type specification for function 'Elixir.HttpProxy.Play.Response':validate/1. The success typing is (map()) -> map()
lib/http_proxy/play/response.ex:69: Function validate/1 has no local return
lib/http_proxy/play/response.ex:73: The call 'Elixir.MapSet':difference(#{'__struct__'=>'Elixir.MapSet', 'map'=>#{#{#<109>(8, 1, 'integer', ['unsigned', 'big']), #<101>(8, 1, 'integer', ['unsigned', 'big']), #<116>(8, 1, 'integer', ['unsigned', 'big']), #<104>(8, 1, 'integer', ['unsigned', 'big']), #<111>(8, 1, 'integer', ['unsigned', 'big']), #<100>(8, 1, 'integer', ['unsigned', 'big'])}#=>[], #{#<112>(8, 1, 'integer', ['unsigned', 'big']), #<97>(8, 1, 'integer', ['unsigned', 'big']), #<116>(8, 1, 'integer', ['unsigned', 'big']), #<104>(8, 1, 'integer', ['unsigned', 'big'])}#=>[], #{#<112>(8, 1, 'integer', ['unsigned', 'big']), #<97>(8, 1, 'integer', ['unsigned', 'big']), #<116>(8, 1, 'integer', ['unsigned', 'big']), #<104>(8, 1, 'integer', ['unsigned', 'big']), #<95>(8, 1, 'integer', ['unsigned', 'big']), #<112>(8, 1, 'integer', ['unsigned', 'big']), #<97>(8, 1, 'integer', ['unsigned', 'big']), #<116>(8, 1, 'integer', ['unsigned', 'big']), #<116>(8, 1, 'integer', ['unsigned', 'big']), #<101>(8, 1, 'integer', ['unsigned', 'big']), #<114>(8, 1, 'integer', ['unsigned', 'big']), #<110>(8, 1, 'integer', ['unsigned', 'big'])}#=>[], #{#<112>(8, 1, 'integer', ['unsigned', 'big']), #<111>(8, 1, 'integer', ['unsigned', 'big']), #<114>(8, 1, 'integer', ['unsigned', 'big']), #<116>(8, 1, 'integer', ['unsigned', 'big'])}#=>[]}, 'version'=>2},_request_key@1::any()) does not have an opaque term of type 'Elixir.MapSet':t(_) as 1st argument
lib/http_proxy/play/response.ex:103: Function 'member_path?'/2 will never be called
lib/http_proxy/play/response.ex:106: Function 'member_body?'/2 will never be called
lib/http_proxy/play/response.ex:109: Function format_error_message/1 will never be called
lib/http_proxy/play/response.ex:139: The pattern <'nil', _> can never match the type <binary(),<<_:_*32>>>
lib/http_proxy/supervisor.ex:32: The pattern 'nil' can never match the type []
lib/http_proxy/utils/file.ex:158: Overloaded contract for 'Elixir.HttpProxy.Utils.File':json_files/1 has overlapping domains; such contracts are currently unsupported and are simply ignored