test-with-docker: install git in the image for dependencies from github

When conda installs dependencies, it will attempt to use git for any dependencies that reference a git repository (e.g. `git+https://github.com/my/repo`)
So git must be installed on the container before dependencies are installed, or it will fail.

setup/tests/Dockerfile

@@ -3,6 +3,7 @@ FROM ubuntu:latest
 
 RUN apt-get update
 RUN apt-get install -y curl
+RUN apt-get install -y git
 
 # CHANGEME: Create the files that correspond to your configuration in the conf directory
 # COPY conf/net/auth/google_auth.json /usr/src/app/conf/net/auth/google_auth.json