PR for #363 enable sphinx autodoc for RTD build (#383)

* Bump eventlet from 0.24.1 to 0.31.0 in /docker/scripts

Bumps [eventlet](https://github.com/eventlet/eventlet) from 0.24.1 to 0.31.0.
- [Release notes](https://github.com/eventlet/eventlet/releases)
- [Changelog](https://github.com/eventlet/eventlet/blob/master/NEWS)
- [Commits](eventlet/eventlet@v0.24.1...v0.31.0)

Signed-off-by: dependabot[bot] <support@github.com>

* #363 silent fail config_site.py loading in case doc build

* #363 silent fail config_site.py loading in case doc build get env var default

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

GeoHealthCheck/init.py

@@ -67,7 +67,10 @@ def init():
 
         # Read and override configs
         app.config.from_pyfile('config_main.py')
-        app.config.from_pyfile('../instance/config_site.py')
+        # config_site.py not present in doc-build: silently fail
+        sphinx_build = os.environ.get('SPHINX_BUILD', '0')
+        app.config.from_pyfile('../instance/config_site.py',
+                               silent=sphinx_build == '1')
         app.config.from_envvar('GHC_SETTINGS', silent=True)
 
         # Global Logging config

docker/scripts/requirements.txt

@@ -1,5 +1,5 @@
 Paver==1.3.4
 psycopg2==2.7.5
-eventlet==0.24.1
+eventlet==0.31.0
 gunicorn==19.9.0
 Werkzeug==0.16.1