Use official cassandra docker image (#1598)

Use the official cassandra docker image. This should hopefully fix the flakiness we've been seeing in our CI with cassandra.

Fixes #1513

Author: Kyle-Verhoog

.circleci/config.yml

@@ -17,7 +17,7 @@ datadog_agent_image: &datadog_agent_image datadog/docker-dd-agent:latest
 redis_image: &redis_image redis:4.0-alpine
 rediscluster_image: &rediscluster_image grokzen/redis-cluster:4.0.9
 memcached_image: &memcached_image memcached:1.5-alpine
-cassandra_image: &cassandra_image spotify/cassandra:latest
+cassandra_image: &cassandra_image cassandra:3.11.7
 consul_image: &consul_image consul:1.6.0
 moto_image: &moto_image palazzem/moto:1.0.1
 elasticsearch_image: &elasticsearch_image elasticsearch:2.3

docker-compose.yml

@@ -7,7 +7,7 @@ services:
         ports:
             - "127.0.0.1:9200:9200"
     cassandra:
-        image: spotify/cassandra:latest
+        image: cassandra:3.11.7
         environment:
             - MAX_HEAP_SIZE=512M
             - HEAP_NEWSIZE=256M