Make Python 3.6 the default version as documented.

charettes · charettes · commit b13b03c88d0a · 2019-02-21T00:02:57.000-05:00
diff --git a/.env b/.env
@@ -1,6 +1,6 @@
-PYTHON_VERSION=3.5
+PYTHON_VERSION=3.6
 POSTGRES_VERSION=9.6
 POSTGIS_VERSION=2.5
 MYSQL_VERSION=8
 MARIADB_VERSION=10.3
-PIP_CACHE_VOLUME=pip-cache
+PIP_CACHE_VOLUME=pip-cache
