[input-output-hk/cardano-sl] Bump LTS-12 (#3459)

parsonsmatt commented on this pull request.

> @@ -349,6 +349,7 @@ instance
where
incorporate =
foldr (uncurry appendToQueryString) req . toQueryString
+ hoistClientMonad _ _ _ _ = error «no hoistClientMonad here»

> Unless you are writing a new backend for servant-client-core or new combinators that you want to support client-generation, you can ignore this class.

oh cool thanks for not putting any docs on the class