Added minimum python release variable

Author: nikhiljohn10

book.json

@@ -3,7 +3,8 @@
     "variables": {
       "py_version": "3.8",
       "py_release": "3.8.6",
-      "py_min_version": "3.6.8",
+      "py_min_version": "3.6",
+      "py_min_release": "3.6.8",
       "pa_py_version": "3.8",
       "django_version": "2.2.4"
     },

en/python_installation/instructions.md

@@ -22,7 +22,7 @@ One thing to watch out for: During the installation, you will notice a window ma
 
 When the installation completes, you may see a dialog box with a link you can follow to learn more about Python or about the version you installed. Close or cancel that dialog -- you'll be learning more in this tutorial!
 
-Note: If you are using an older version of Windows (7, Vista, or any older version) and the Python {{ book.py_version }} installer fails with an error, then install all Windows Updates and try to install Python again. If you still have the error, try installing Python version {{ book.py_min_version }} from [Python.org](https://www.python.org/downloads/windows/).
+Note: If you are using an older version of Windows (7, Vista, or any older version) and the Python {{ book.py_version }} installer fails with an error, then install all Windows Updates and try to install Python again. If you still have the error, try installing Python version {{ book.py_min_release }} from [Python.org](https://www.python.org/downloads/windows/).
 
 > Django {{ book.django_version }} needs Python {{ book.py_min_version }} or greater, which does not support Windows XP or earlier versions.
 
@@ -51,7 +51,7 @@ $ python3 --version
 Python {{ book.py_release }}
 ```
 
-If you have a different version of Python installed, at least {{ book.py_min_version }} (e.g. {{ book.py_release }}), then you don't have to upgrade. If you don't have Python installed, or if you want a different version, first check what Linux distribution you are using with the following command:
+If you have a different version of Python installed, at least {{ book.py_min_version }} (e.g. {{ book.py_min_release }}), then you don't have to upgrade. If you don't have Python installed, or if you want a different version, first check what Linux distribution you are using with the following command:
 
 {% filename %}command-line{% endfilename %}
 ```