Update README for new Elm tagging convention

Author: avh4

PUBLISHING.md

@@ -4,4 +4,4 @@
 1. Push the new tag `git push origin v<new version>`
 1. Wait for the tag to pass CI <https://travis-ci.org/avh4/elm-upgrade>
 1. Make sure you have the tag checked out, and `npm publish`
-1. Add the helper dist tags `npm dist-tag add elm-upgrade@<new version> elm0.19.0`
+1. Add the helper dist tags `npm dist-tag add elm-upgrade@<new version> latest-0.19.1`

README.md

@@ -21,12 +21,12 @@ If you are already using Elm 0.19, `elm-upgrade` will to the following:
 
 ## How to use **elm-upgrade**
 
-First install Elm 0.19 and the latest version of [elm-format](https://github.com/avh4/elm-format#installation-).  (If you want to install them locally for your project, you can do so with the following: )
+First install Elm 0.19.1 and the latest version of [elm-format](https://github.com/avh4/elm-format#installation-).  (If you want to install them locally for your project, you can do so with the following: )
 
 ```sh
 cd path/to/my/elm/project
-npm install elm@elm0.19.0
-npm install elm-format@elm0.19.0
+npm install elm@latest-0.19.1
+npm install elm-format@latest-0.19.1
 ```
 
 Then run the following in your terminal: