Upgrading to 0.33 leads to 'Unable to determine AWS region' error

[KnisterPeter]

Describe the bug
Since upgrading to version 0.33 we could not run any CDK command. It fails with the following error:

(node:31487) UnhandledPromiseRejectionWarning: Error: Unable to determine AWS region from environment or AWS configuration (profile: "xxx")
    at getCLICompatibleDefaultRegion (/xxx/node_modules/aws-cdk/lib/api/util/sdk.ts:357:11)
(node:31487) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:31487) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Version:

• OS: Arch Linux
• Programming Language: TypeScript
• CDK Version: 0.33

[rix0rrr]

Duplicate of #2697