Add APIStar requirements for schema generation

ci/openapi.sh

 #!/bin/sh -e
 mkdir -p output
 pip install -e .
-pip install uritemplate==3 apistar>=0.7.2
 PONOS_DATA_DIR=/tmp arkindex/manage.py generateschema --generator_class arkindex.project.openapi.SchemaGenerator > output/schema.yml

requirements.txt

 # -r ./base/requirements.txt
 
 arkindex-common==0.2.0
+apistar==0.7.2
 certifi==2017.7.27.1
 channels==2.3.1
 channels-redis==2.4.1
@@ -25,4 +26,6 @@ responses==0.10.7
 requests==2.22
 sentry-sdk==0.14.3
 urllib3==1.22
+uritemplate==3
 git+https://gitlab.com/arkindex/common.git#egg=arkindex-common
+git+https://gitlab.com/teklia/apistar.git#egg=apistar

tests-requirements.txt

@@ -2,6 +2,5 @@ flake8==3.6.0
 tripoli
 django-nose
 coverage
-uritemplate==3
 responses
 mock~=4.0.0