docs: Add AWS credentials configuration prerequisites

- Document requirement for AWS credentials configuration using default provider chain
- Add examples for different credential configuration methods (aws configure, env vars, IAM roles)
- Update both README.md and connection reference documentation
- Clarify that RDS Signer uses default credential provider chain as per AWS documentation

Author: fab0492

docs/docs/connection-reference.md

@@ -94,6 +94,12 @@ node dist/src/index.js --mysql --host localhost --database sample_db --port 3306
 
 ### AWS IAM Authentication Example
 
+**Prerequisites:** AWS credentials must be configured using the default credential provider chain:
+- `aws configure` (default profile) 
+- `AWS_PROFILE=myprofile` environment variable
+- `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` environment variables
+- IAM roles (if running on EC2)
+
 ```bash
 node dist/src/index.js --mysql --aws-iam-auth --host rds-endpoint.region.rds.amazonaws.com --database sample_db --user aws-username --aws-region us-east-1
 ```

readme.md

@@ -117,6 +117,14 @@ Optional parameters:
 
 For Amazon RDS MySQL instances with IAM database authentication:
 
+**Prerequisites:**
+- AWS credentials must be configured (the RDS Signer uses the default credential provider chain)
+- Configure using one of these methods:
+  - `aws configure` (uses default profile)
+  - `AWS_PROFILE=myprofile` environment variable
+  - `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` environment variables
+  - IAM roles (if running on EC2)
+
 ```
 node dist/src/index.js --mysql --aws-iam-auth --host <rds-endpoint> --database <database-name> --user <aws-username> --aws-region <region>
 ```