dynamodb-encryption-client Integration Tests

In order to run these integration tests successfully, these things which must be configured.

1. These tests assume that AWS credentials are available in one of the automatically discoverable credential locations.
2. The AWS_ENCRYPTION_SDK_PYTHON_INTEGRATION_TEST_AWS_KMS_KEY_ID environment variable must be set to a valid AWS KMS CMK ARN that can be used by the available credentials.
3. The AWS_ENCRYPTION_SDK_PYTHON_INTEGRATION_TEST_AWS_KMS_MRK_KEY_ID and AWS_ENCRYPTION_SDK_PYTHON_INTEGRATION_TEST_AWS_KMS_MRK_KEY_ID_2 environment variables must be set to two related AWS KMS Multi-Region key ids in different regions.
4. The DDB_ENCRYPTION_CLIENT_TEST_TABLE_NAME environment variable must be set to a valid DynamoDB table name, in the default region, to which the discoverable credentials have read, write, and describe permissions.

Updating Upstream Requirements

The purpose of the upstream requirements files is to provide a stable list of packages for dependencies to run downstream tests of the DynamoDB Encryption Client. In order to update the upstream requirements in upstream-requirements-py37.txt, run these commands:

$ tox -e freeze-upstream-requirements-py37

Test them using:

$ tox -e test-upstream-requirements-py37