Update Readme

Pip installer should use pip3

README.md

@@ -47,7 +47,7 @@ In order to run this app in Linux environment, you'll need the following package
 
 2. Run the pip installation
 
-    `pip install .`
+    `pip3 install .`
     
 2. Once completed run with the following command
 
@@ -75,4 +75,4 @@ Original application by Rune B. Broberg (5Q5R)
 
 TDR inspiration shamelessly stolen from the work of Salil (VU2CWA) at https://nuclearrambo.com/wordpress/accurately-measuring-cable-length-with-nanovna/
 
-Thanks to everyone who have tested, commented and inspired.
+Thanks to everyone who have tested, commented and inspired.