This pull request includes several changes to add support for custom S3 endpoints and improve testing capabilities. The most important changes include updates to the workflow configuration, the main application logic, and the S3 state reading functionality.

Workflow Configuration:

• .github/workflows/test.yml: Updated the Go version matrix to include 1.23 and added MinIO service configuration for local S3 testing. Environment variables for MinIO are also set for the build and test steps. [1] [2]

Application Logic:

• cmd/tfstate-lookup/main.go: Added a new command-line flag s3-endpoint-url to specify a custom S3 endpoint URL. Set the corresponding environment variable if the flag is provided. [1] [2]

S3 State Reading:

• tfstate/lookup.go: Modified the readS3 function to accept and use a custom S3 endpoint URL from the environment variable. Updated the S3Option struct to include Endpoint.
• tfstate/remote_s3.go: Refactored the S3 option handling to include AccessKey, SecretKey, and Endpoint. Added support for static credentials and custom endpoints in the S3 client configuration. [1] [2] [3]

Testing:

• tfstate/remote_s3_test.go: Added a new test TestReadS3 to verify reading from an S3 bucket using a custom endpoint. [1] [2]