We're using an old version of `boto` (through `moto`) to detect the available regions for Lambda (and other APIs). We should switch from `boto` to the newer `boto3` library, which includes the up-to-date endpoints.

```
code/localstack/localstack/services/cloudformation/cloudformation_starter.py", line 502, in Lambda_create_from_cloudformation_json
    return Lambda_create_from_cloudformation_json_orig(resource_name, cloudformation_json, region_name)
  File "/opt/code/localstack/.venv/lib/python3.7/site-packages/moto/awslambda/models.py", line 519, in create_from_cloudformation_json
    backend = lambda_backends[region_name]
KeyError: 'eu-west-2'
```
import sys
import json
import logging
import traceback
import six
from moto.s3 import models as s3_models
from moto.iam import models as iam_models
from moto.sqs import models as sqs_models
from moto.core import BaseModel
from moto.server import main as moto_main
from moto.kinesis import models as kinesis_models
from moto.dynamodb import models as dynamodb_models
from moto.dynamodb2 import models as dynamodb2_models
from moto.awslambda import models as lambda_models
from moto.apigateway import models as apigw_models