Add link to hackage package to readme (#1313)

* Add link to hackage package to readme

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* Add hackage badge

Co-authored-by: Potato Hatsue <berberman@yandex.com>
Co-authored-by: Junyoung/Clare Jang <jjc9310@gmail.com>

Author: 3 people

README.md

@@ -2,6 +2,7 @@
 
 ![haskell-language-server][logo]
 
+[![Hackage][badge-hackage]][hackage]
 [![License Apache 2.0][badge-license]][license]
 [![CircleCI][badge-circleci]][circleci]
 ![Github Testing Workflow](https://github.com/haskell/haskell-language-server/workflows/Testing/badge.svg)
@@ -12,6 +13,8 @@
 [license]: https://github.com/haskell/haskell-language-server/blob/master/LICENSE
 [badge-circleci]: https://img.shields.io/circleci/project/github/haskell/haskell-language-server/master.svg
 [circleci]: https://circleci.com/gh/haskell/haskell-language-server/
+[badge-hackage]: https://img.shields.io/hackage/v/haskell-language-server.svg?logo=haskell
+[hackage]: https://hackage.haskell.org/package/haskell-language-server
 
 Integration point for [ghcide](https://github.com/haskell/ghcide) and [haskell-ide-engine](https://github.com/haskell/haskell-ide-engine). One IDE to rule
 them all. Read the [project's
@@ -257,6 +260,8 @@ Direct installation from Hackage, while possible via `cabal install haskell-lang
 Said command builds the `haskell-language-server` binary and installs it in the default Cabal binaries folder,
 but the binary will only work with projects that use the same GHC version that built it.
 
+The package can be found here on Hackage: https://hackage.haskell.org/package/haskell-language-server
+
 ## Configuring `haskell-language-server`
 
 Language servers like `haskell-language-server` expose most of their configuration via the client (i.e. the editor).