fix: improve example & fix userinfo marshal (#132)

* fix: example client should track state, call cli.CodeFlow need context

* fix: oidc userinfo can UnmarshalJSON with address

* rp Discover use client.Discover

* add instruction for example to README.md

pkg/oidc/userinfo_test.go

@@ -0,0 +1,26 @@
+package oidc
+
+import (
+	"encoding/json"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestUserInfoMarshal(t *testing.T) {
+	userinfo := NewUserInfo()
+	userinfo.SetSubject("test")
+	userinfo.SetAddress(NewUserInfoAddress("Test 789\nPostfach 2", "", "", "", "", ""))
+	userinfo.SetEmail("test", true)
+	userinfo.SetPhone("0791234567", true)
+	userinfo.SetName("Test")
+	userinfo.AppendClaims("private_claim", "test")
+
+	marshal, err := json.Marshal(userinfo)
+	out := NewUserInfo()
+	assert.NoError(t, err)
+	assert.NoError(t, json.Unmarshal(marshal, out))
+	assert.Equal(t, userinfo.GetAddress(), out.GetAddress())
+	expected, err := json.Marshal(out)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, marshal)
+}