Log Message:
0.20.2
----
- Full query string helpers \ 
[#1604](https://github.com/haskell-servant/servant/pull/1604)

  This PR introduces `DeepQuery`, a route combinator that implements a pattern \ 
commonly known as deep objects.
  It builds upon the convention of using `[]` for a list of parameters:
  `books?filter[search]=value&filter[author][name]=value`.
  The corresponding type would be `DeepQuery "filter" BookQuery :> \ 
Get '[JSON] [Book]`.
- Add IsIn instance for NamedRoutes \ 
[#1707](https://github.com/haskell-servant/servant/pull/1707)
- Renamed `AtLeastOneFragment` type class to `AtMostOneFragment` \ 
[#1727](https://github.com/haskell-servant/servant/pull/1727)

  The previously named `AtLeastOneFragment` type class defined in the
  `Servant.API.TypeLevel` module has been renamed to `AtMostOneFragment`,
  since the previous name was misleading.
- Use `Header'` in response headers. \ 
[#1697](https://github.com/haskell-servant/servant/pull/1697)

  Use `Header'` instead of `Header` in response, so it's possible to provide
  `Description`, for example:

  ```
  type PaginationTotalCountHeader =
    Header'
      '[ Description "Indicates to the client total count of items in \ 
collection"
       , Optional
       , Strict
       ]
      "Total-Count"
      Int
  ```

  Note: if you want to add header with description you should use `addHeader'`
  or `noHeader'` which accepts `Header'` with all modifiers.