[doc] Updated streaming response limit to 200 MB

[dsplatonov]

Motivation:

AWS Lambda response streaming now supports a default maximum response payload size of 200 MB (increased from 20 MB). This update aligns the documentation with the new AWS limits.

Modifications:

• Updated readme.md: Changed "soft limit of 20 MB" to "default maximum response payload size of 200 MB"
• Updated Examples/Streaming/README.md: Same change as above
• Updated terminology to match AWS official documentation

Result:

Documentation now accurately reflects the current AWS Lambda streaming response limits, enabling users to understand they can stream up to 200 MB payloads.

Reference: https://aws.amazon.com/about-aws/whats-new/2025/07/aws-lambda-response-streaming-200-mb-payloads/

[sebsto]

Thank you @dsplatonov !
Your change will fix #546

But I think there is a bit more than the doc to check. I know the LambdaRuntimeClient struct has several references to the 6Mb payload limit for non-streaming operations. We need to make sure there is no 20Mb limit hardcoded here and there.

[dsplatonov]

Yea, I’ve checked all files, found 20 mb only in documentation, 6mb limit is not changed, so I didn’t change it in code:)

[sebsto]

LGTM. I also checked for hard-code 20Mb limit in the code and could not find any.