add python 3.8

Author: Sumito Tsukada

README.md

@@ -1,6 +1,6 @@
 # ImageMagick for AWS Lambda
 
-Scripts to compile ImageMagick utilities for AWS Lambda instances powered by Amazon Linux 2.x, such as the `nodejs10.x` or `nodejs12.x` runtime, and the updated 2018.03 Amazon Linux 1 runtimes. 
+Scripts to compile ImageMagick utilities for AWS Lambda instances powered by Amazon Linux 2.x, such as the `nodejs10.x` or `nodejs12.x` or `python 3.8` runtime, and the updated 2018.03 Amazon Linux 1 runtimes. 
 
 Amazon Linux 2 instances for Lambda no longer contain system utilities, so `convert`, `mogrify` and `identify` from the [ImageMagick](https://imagemagick.org) package are no longer available.