Update cli.md (#313)

Changes typo from "hello" to "python" in invoke command

Co-authored-by: Nicki Skafte Detlefsen <skaftenicki@gmail.com>

s2_organisation_and_version_control/cli.md

@@ -321,7 +321,7 @@ easier.
     returns the current Python interpreter but it works for all operating systems. Check that it works by running:
 
     ```bash
-    invoke hello
+    invoke python
     ```
 
 4. Lets try to create a task that simplifies the process of `git add`, `git commit`, `git push`. Create a task such