Add support for Python 3.8.6 (#1072)

https://www.python.org/downloads/release/python-386/
https://pythoninsider.blogspot.com/2020/09/python-386-is-now-available.html

Closes @W-7791243@.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Python 3.8.6 is now available (CPython) (#1072).
 
 ## v179 (2020-09-23)
 

README.md

@@ -62,7 +62,7 @@ Specify a Python Runtime
 
 Supported runtime options include:
 
-- `python-3.8.5`
+- `python-3.8.6`
 - `python-3.7.9`
 - `python-3.6.12`
 - `python-2.7.18`

bin/default_pythons

@@ -6,7 +6,7 @@
 # shellcheck disable=2034
 
 DEFAULT_PYTHON_VERSION="python-3.6.12"
-LATEST_38="python-3.8.5"
+LATEST_38="python-3.8.6"
 LATEST_37="python-3.7.9"
 LATEST_36="python-3.6.12"
 LATEST_35="python-3.5.10"

builds/runtimes/python-3.8.6

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3