Update base docker image

[geohacker]

This PR updates the base docker image from debian jessie to debian buster. It's essential to do this for fetching new packages for GDAL for using with geo django models.

Changes

• Dockerfile uses a new image
• Updates some dependencies like Markupsafe and setuptools
• Remove pygraphviz as per conversation with @batpad

Checklist

Things that should succeed before merging.

• Updated/ran unit tests
• Updated CHANGELOG.md

Release

If there is a version update, make sure to tag the repository with the latest version.

[batpad]

This looks fine to me @geohacker - pygraphviz was only used to be able to generate this graph of all the models as a management command. We can live without it, and I'm the only person who used that as far as I know. It will definitely be good to have some testing, but I think it's a good time to merge in changes like this, and I overall like the idea of updating our docker base image to a newer Debian.

@thenav56 @GregoryHorvath could you please take a look and approve if this seems all fine to you?

[GergiH]

The whole thing ran smoothly for me, I only got 2 errors but these are there for ages now so I guess there's in action to do there:

debconf: delaying package configuration, since apt-utils is not installed

ERROR: elasticsearch 6.0.0 has requirement urllib3<1.23,>=1.21.1, but you'll have urllib3 1.24.2 which is incompatible.

cc @batpad

[GergiH]

@geohacker should I deploy this to staging then asap?

[geohacker]

@GregoryHorvath I'll just fix the minor thing @thenav56 pointed out and then we can deploy to staging!

[GergiH]

@geohacker deployed

[nanometrenat]

Released this morning I am told