Add issue approver output and enhance approval logic

- Updated action outputs to include the GitHub username of the approver.
- Modified approval logic to return the approver's username upon approval or denial.
- Enhanced tests to validate the new approver output.

Rename 'issue-approver' to 'issue-responder' for clarity in approval process

Makefile

@@ -1,5 +1,6 @@
 IMAGE_REPO=ghcr.io/trstringer/manual-approval
 TARGET_PLATFORM=linux/amd64,linux/arm64,linux/arm/v8
+GO_DOCKER_IMAGE=golang:1.24
 
 .PHONY: tidy
 tidy:
@@ -28,6 +29,10 @@ build_push:
 test:
 	go test -v .
 
+.PHONY: test_docker
+test_docker:
+	docker run --rm -v $$(pwd):/app -w /app $(GO_DOCKER_IMAGE) sh -c "go mod tidy && go test -v ."
+
 .PHONY: lint
 lint:
 	docker run --rm -v $$(pwd):/app -w /app golangci/golangci-lint:v2.1.6 golangci-lint run -v