[docs] Enable dynamic compression on docs.python.org

[INADA Naoki]

Hi,

I notice that docs.python.org doesn't serve compressed contents.

I believe docs.python.org uses Fastly.
And Fastly has dynamic automatic gzipping.
https://docs.fastly.com/guides/basic-configuration/enabling-automatic-gzipping

I think it's very nice for many visitors.  And it's easier than configure
gzip_static on nginx.

How about enabling it?

Regards,

INADA Naoki  <songofacandy at gmail.com>