Docs: user guide hard-codes us-east-1

[rddefauw]

Describe the issue

In the user guide, the CLI configuration step hard-codes us-east-1:

node lib/bin/bgagent.js configure \
  --api-url $API_URL \
  --region us-east-1 \
  --user-pool-id $USER_POOL_ID \
  --client-id $APP_CLIENT_ID

It should have the user set a variable for the REGION and then use that. Otherwise it's easy to copy and paste this section when you've deployed to a different region. If you do that, you'll get a somewhat confusing error message about the cognito app client not existing.

Affected docs

https://github.com/aws-samples/sample-autonomous-cloud-coding-agents/blob/main/docs/guides/USER_GUIDE.md

Suggested change

No response

[krokoko]

Thank you, good catch ! Updated in c1fdeb1