fix: make checkKey public

pkg/rp/jws.go

@@ -0,0 +1,15 @@
+package rp
+
+import (
+	"gopkg.in/square/go-jose.v2"
+)
+
+func CheckKey(keyID string, keys []jose.JSONWebKey, jws *jose.JSONWebSignature) ([]byte, error, bool) {
+	for _, key := range keys {
+		if keyID == "" || key.KeyID == keyID {
+			payload, err := jws.Verify(&key)
+			return payload, err, true
+		}
+	}
+	return nil, nil, false
+}