Update helpers to reference python3.8 from python3.6

Author: conradho

helpers/1-start_python.md

@@ -30,8 +30,8 @@ by clicking the PythonAnywhere logo in the top left.
 ----
 
 Click on the ">>> Python" button in the "New console" section below (underneath
-the Recent Consoles section), then on the **3.6** button in the menu that
-appears; this will start Python version 3.6, which is a good version to start
+the Recent Consoles section), then on the **3.8** button in the menu that
+appears; this will start Python version 3.8, which is a good version to start
 off with. After a little while, you should see a console with a "prompt" that
 looks like this:
 

helpers/3-web_app.md

@@ -97,7 +97,7 @@ hit the right arrow below to go to the next step.
 **New Web App Wizard**
 
 The next choice is which version of Python (and its associated version of
-Flask) you want to use.  For this tutorial we'll use Python 3.6.  Click the
+Flask) you want to use.  For this tutorial we'll use Python 3.8.  Click the
 link for it, then click the right arrow for the next step.
 
 

helpers/6-education.md

@@ -28,7 +28,7 @@ For now, let's start a bash console. Find the `$ Bash` button under the Consoles
 
 This should take you to a new page. In your Bash console, type:
 
-    python3.6
+    python3.8
     >>> print("Hello world")
 
 You'll see Python works the way you expect it to. Press Ctrl+D to exit.
@@ -53,7 +53,7 @@ write some more Python code:
 
 
 You can save your file, and if you wanted to you could go back to a Bash
-console and run it from the command-line with `python3.6 hello.py`. But there's
+console and run it from the command-line with `python3.8 hello.py`. But there's
 a shortcut right on this page -- click the light blue button that says `>>>
 Run` to save and run your file.