Update install.md to refer to version 1.11.1

Author: abulford

compose/install.md

@@ -34,7 +34,7 @@ To install Compose, do the following:
     The following is an example command illustrating the format:
 
     ```bash
-    $ curl -L "https://github.com/docker/compose/releases/download/1.10.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
+    $ curl -L "https://github.com/docker/compose/releases/download/1.11.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
     ```
 
     If you have problems installing with `curl`, see