Django bugfix releases: 2.1.7, 2.0.12 and 1.11.20

Today we've issued the 2.1.7, 2.0.12 and 1.11.20 bugfix releases.

The release package and checksums are available from our downloads page, as well as from the Python Package Index. The PGP key ID used for this release is Carlton Gibson: E17DF5C82B4F9D00.