Release 20.4.0 broken for kube-web-view

[hjacobs]

I had to roll back the 20.4.0 release as it's broken:

INFO:kube_web.resource_registry:Initializing resource registry for https://127.0.0.1:45867..
DEBUG:kube_web.resource_registry:Getting resource types for https://127.0.0.1:45867..
DEBUG:urllib3.connectionpool:Starting new HTTPS connection (1): 127.0.0.1:45867
DEBUG:urllib3.connectionpool:https://127.0.0.1:45867 "GET /api/v1/ HTTP/1.1" 200 None
DEBUG:urllib3.connectionpool:https://127.0.0.1:45867 "GET /apis/apis/ HTTP/1.1" 404 19
DEBUG:kube_web.web:Exception on /clusters/kind-kube-web-view-e2e: 404 Client Error: Not Found for url: https://127.0.0.1:45867/apis/apis/
ERROR:kube_web.web:Server Error: 404 Client Error: Not Found for url: https://127.0.0.1:45867/apis/apis/
Traceback (most recent call last):
  File "/home/hjacobs/workspace/kube-web-view/kube_web/web.py", line 1332, in error_handler
    response = await handler(request)
  File "/home/hjacobs/workspace/kube-web-view/kube_web/web.py", line 1402, in trailing_slash
    response = await handler(request)
  File "/home/hjacobs/.cache/pypoetry/virtualenvs/kube-web-view-8vgWinVm-py3.8/lib/python3.8/site-packages/aiohttp_jinja2/__init__.py", line 122, in wrapped
    context = await coro(*args)
  File "/home/hjacobs/workspace/kube-web-view/kube_web/web.py", line 315, in func_wrapper
    ctx = await func(request, session)
  File "/home/hjacobs/workspace/kube-web-view/kube_web/web.py", line 412, in get_cluster
    resource_types = await cluster.resource_registry.cluster_resource_types
  File "/home/hjacobs/workspace/kube-web-view/kube_web/resource_registry.py", line 155, in cluster_resource_types
    await self.initialize()
  File "/home/hjacobs/workspace/kube-web-view/kube_web/resource_registry.py", line 131, in initialize
    async for clazz in get_namespaced_resource_types(self.api):
  File "/home/hjacobs/workspace/kube-web-view/kube_web/resource_registry.py", line 102, in get_namespaced_resource_types
    async for namespaced, api_version, resource in discover_api_resources(api):
  File "/home/hjacobs/workspace/kube-web-view/kube_web/resource_registry.py", line 44, in discover_api_resources
    r.raise_for_status()
  File "/home/hjacobs/.cache/pypoetry/virtualenvs/kube-web-view-8vgWinVm-py3.8/lib/python3.8/site-packages/requests/models.py", line 941, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://127.0.0.1:45867/apis/apis/

This is most probably caused by #59