add django-hosts as a dependency

Used to allow the council climate league to be in the same django
project. Included from github as they don't seem to be great at point
releases

requirements.txt

@@ -17,6 +17,7 @@ djangorestframework==3.12.4
 django-simple-history==3.0.0
 -e git+https://github.com/mysociety/django-pipeline@c67514ae828f79454320a37b0aeb154c7359e19c#egg=django_pipeline
 -e git+https://github.com/mysociety/django-pipeline-csscompressor@6a88fde5045d68746f1c7ee816deda86615c5581#egg=django_pipeline_csscompressor
+git+https://github.com/jazzband/django-hosts/@55634e5dd5cce33619dcb641c5e3c6a9c85e7caa#egg=django_hosts
 et-xmlfile==1.0.1
 feedparser==5.2.1
 future-fstrings==1.2.0