hardcode PythonAnywhere Python version to 3.8

fixes DjangoGirls#1694

Author: das-g

en/deploy/README.md

@@ -176,7 +176,7 @@ Deploying a web app on PythonAnywhere involves pulling down your code from GitHu
 
 {% filename %}PythonAnywhere command-line{% endfilename %}
 ```
-$ pip{{ book.pa_py_version }} install --user pythonanywhere
+$ pip3.8 install --user pythonanywhere
 ```
 
 That should print out some things like `Collecting pythonanywhere`, and eventually end with a line saying `Successfully installed (...) pythonanywhere- (...)`.
@@ -185,7 +185,7 @@ Now we run the helper to automatically configure our app from GitHub. Type the f
 
 {% filename %}PythonAnywhere command-line{% endfilename %}
 ```
-$ pa_autoconfigure_django.py --python={{ book.pa_py_version }} https://github.com/<your-github-username>/my-first-blog.git
+$ pa_autoconfigure_django.py --python=3.8 https://github.com/<your-github-username>/my-first-blog.git
 ```
 
 As you watch that running, you'll be able to see what it's doing: