Change 'wait' to use 'between' as recommended by locustio (#298)

src/loadgenerator/locustfile.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 import random
-from locust import HttpLocust, TaskSet
+from locust import HttpLocust, TaskSet, between
 
 products = [
     '0PUK6V6EV0',
@@ -78,5 +78,4 @@ class UserBehavior(TaskSet):
 
 class WebsiteUser(HttpLocust):
     task_set = UserBehavior
-    min_wait = 1000
-    max_wait = 10000
+    wait_time = between(1, 10)

src/loadgenerator/requirements.in

@@ -1 +1 @@
-locustio==0.8.1
+locustio==0.13.0

src/loadgenerator/requirements.txt

@@ -13,7 +13,7 @@ greenlet==0.4.15          # via gevent
 idna==2.8                 # via requests
 itsdangerous==1.1.0       # via flask
 jinja2==2.10              # via flask
-locustio==0.8.1
+locustio==0.13.0
 markupsafe==1.1.0         # via jinja2
 msgpack-python==0.5.6     # via locustio
 pyzmq==17.0.0             # via locustio