feat: add readiness probe

pkg/handler/ready.go

@@ -0,0 +1,16 @@
+package handler
+
+import (
+	"net/http"
+)
+
+type readyHandler struct{}
+
+// NewReadyHandler returns a readiness probe handler.
+func NewReadyHandler() (http.Handler, error) {
+	return &readyHandler{}, nil
+}
+
+func (h *readyHandler) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
+	w.WriteHeader(http.StatusOK)
+}