Switching PL/Python to Python 3 by default in PostgreSQL 12

Greetings:

I am not sure if this has been brought up before but Python 2 is EOL on Jan 1 2020. After that time there will not be any security fixes or patches.

According to our most recent official documentation:
https://www.postgresql.org/docs/11/plpython-python23.html

I know we are late in the Postgresql 12 cycle but I think switching the default to Python 3 is warranted given:

1. The serious nature of not having a default supported Python version soon after the PostgreSQL 12 release

2. The next opportunity to change the default will be late 2020

If we do not switch our default version and a vulnerability arises in Python 2 then we will end up either

1. Telling our users to run the default PL/Python with a known security vulnerability

2. The PostgreSQL community patching it's python

I know there are implications for swapping the default version but I think that is outweighed by the seriousness of the situation.

Thanks

Steve