CVE-2019-6975 -- Django fixed memory exhaustion in utils.numberformat.format().

[Carlton Gibson <carlton.gibson () gmail com>]

In accordance with our security release policy, the Django team is issuing Django 1.11.19, Django 2.1.6, and Django 
2.0.11. These releases addresses the security issue detailed below. We encourage all users of Django to upgrade as soon 
as possible.

CVE-2019-6975: Memory exhaustion in django.utils.numberformat.format()

If django.utils.numberformat.format() -- used by contrib.admin as well as the the floatformat, filesizeformat, and 
intcomma templates filters -- received a Decimal with a large number of digits or a large exponent, it could lead to 
significant memory usage due to a call to '{:f}'.format().

To avoid this, decimals with more than 200 digits are now formatted using scientific notation.

See Django blog for more details and download links: 
https://www.djangoproject.com/weblog/2019/feb/11/security-releases/ 
<https://www.djangoproject.com/weblog/2019/feb/11/security-releases/>