Fix install command

Author: Kevin D Smith

README.md

@@ -21,7 +21,7 @@ SAS pipefitter can be installed as follows with `pip`:
 
 Alternatively, you can install a specific release as follows:
 
-    pip install pip install https://github.com/sassoftware/python-pipefitter/releases/download/vX.X.X/pipefitter-X.X.X.tar.gz
+    pip install https://github.com/sassoftware/python-pipefitter/releases/download/vX.X.X/pipefitter-X.X.X.tar.gz
 
 ## Dependencies