Fix plugins related text in README.md

Signed-off-by: Ulysses Souza <ulysses.souza@docker.com>

README.md

@@ -189,10 +189,11 @@ Removing network hello_default
 
 Pre-built binaries are available on [GitHub releases](https://github.com/docker/app/releases) for Windows, Linux and macOS.
 Each tarball contains two binaries:
-- `docker-app-plugin-{linux|macos|windows}` which is docker-app as a [docker cli plugin](https://github.com/docker/cli/issues/1534) 
-- `docker-app-standalone-{linux|macos|windows}` which is docker-app as a standalone utility 
+- `docker-app-plugin-{linux|darwin|windows.exe}` which is docker-app as a [docker cli plugin](https://github.com/docker/cli/issues/1534). **Note**: This requires a pre-release version of the 
+Docker CLI 
+- `docker-app-standalone-{linux|darwin|windows.exe}` which is docker-app as a standalone utility
 
-To use `docker-app` plugin, just type `docker app` instead of `docker-app` and all the examples will work the same way:
+To use the `docker-app` plugin, just type `docker app` instead of `docker-app` and all the examples will work the same way:
 ```bash
 $ docker app version
 Version:      v0.8
@@ -250,8 +251,6 @@ cp docker-app-plugin-windows.exe ~/.docker/cli-plugins/docker-app.exe
 ```
 
 
-**Note:** To use Application Packages as images (i.e.: `save`, `push`, or `install` when package is not present locally) on Windows, one must be in Linux container mode.
-
 ## Single file or directory representation
 
 If you prefer having the three core documents in separate YAML files, omit the `-s` / `--single-file` option to