Change Image Analysis Image

Due to docker pull limits we need to either switch the test image from centos:latest to something internally hosted or add a docker login:

Initiating image analysis...
DEBUG:anchorecli.clients.apiexternal:As Account = None DEBUG:urllib3.connectionpool:Starting new HTTPS connection (1): anchore-api.bigbang.dev:443 DEBUG:urllib3.connectionpool:https://anchore-api.bigbang.dev:443 "GET /v1 HTTP/1.1" 200 5 DEBUG:anchorecli.clients.apiexternal:As Account = None DEBUG:anchorecli.clients.apiexternal:POST url=https://anchore-api.bigbang.dev/v1/images?autosubscribe=True DEBUG:urllib3.connectionpool:Starting new HTTPS connection (1): anchore-api.bigbang.dev:443 DEBUG:urllib3.connectionpool:https://anchore-api.bigbang.dev:443 "POST /v1/images?autosubscribe=True HTTP/1.1" 400 745 DEBUG:anchorecli.cli.utils:fetched httpcode from response: 400 Error: cannot fetch image digest/manifest from registry HTTP Code: 400 Detail: {'error_codes': ['SKOPEO_UNKNOWN_ERROR'], 'raw_exception_message': 'Error encountered in skopeo operation. cmd=/bin/sh -c skopeo inspect --raw --tls-verify=false docker://docker.io/library/centos:latest, rc=1, stdout=None, stderr=b\'time="2021-10-11T17:52:07Z" level=fatal msg="Error parsing image name \\\\"docker://docker.io/library/centos:latest\\\\": Error reading manifest latest in docker.io/library/centos: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit"\\n\', error_code=SKOPEO_UNKNOWN_ERROR'}