pin nightly to pygeoapi 0.16.1 (#327)

Author: tomkralidis

Dockerfile

@@ -44,7 +44,7 @@ RUN apt-get update && \
     apt-get install -y python3 python3-setuptools python3-pip git curl unzip python3-click python3-fiona python3-gdal python3-lxml python3-parse python3-pyproj python3-rasterio python3-requests python3-slugify python3-sqlalchemy python3-unicodecsv python3-xarray python3-yaml
 
 # install pygeoapi
-RUN git clone $PYGEOAPI_GITREPO && \
+RUN git clone $PYGEOAPI_GITREPO -b 0.16.1 && \
     cd pygeoapi && \
     pip3 install -r requirements.txt && \
     pip3 install flask_cors gunicorn gevent greenlet && \