start: env var errors with invalid config file

Got an error while trying to setup cluster with Tarantool 3.0.0-alpha3.

tree
.
├── config.yml
├── init.lua
├── instances.yml
├── tt.yaml
├── var
...

Config.yml = instances.yml =

instance_000:
...

I don't have actual steps to reproduce, but I think the problem is in the config.yml file that is the same as instances.yml

tt init 

export TT_CONFIG_ETCD_ENDPOINTS="http://127.0.0.1:2379"
export TT_CONFIG_ETCD_HTTP_REQUEST_TIMEOUT=30.1
tt start
   ⨯ third_party: can't find an application init file: unable to parse cluster config from file: failed to parse a configuration data as a cluster config: failed to unmarshal ClusterConfig: yaml: unmarshal errors:
  line 3: cannot unmarshal !!str http://... into []string
  line 6: cannot unmarshal !!str 30.1 into float64

...


unset TT_CONFIG_ETCD_ENDPOINTS
unset TT_CONFIG_ETCD_HTTP_REQUEST_TIMEOUT
tt start
   ⨯ third_party: can't find an application init file: an instance "instance_004" not found

Begin with the tt start path and the config.yml and instances.yml inputs, using the shown environment variables and commands as the starting point. The report has no reliable reproduction steps; done means confirming how the invalid cluster configuration leads to the parse and missing-instance errors and verifying the corrected behavior.