feat: json2go (#130)

* feat(json2go): implement

* feat(json2go): support manual input

* chore(readme): add json2go

* chore(docs): add docs

spec/fixtures/json2go/interativly_input.go

@@ -0,0 +1,2 @@
+package main
+

spec/fixtures/json2go/interativly_output.go

@@ -0,0 +1,5 @@
+package main
+
+type AutoGenerated struct {
+	Json bool `json:"json"`
+}

spec/fixtures/json2go/manual_input.go

@@ -0,0 +1,2 @@
+package main
+

spec/fixtures/json2go/manual_output.go

@@ -0,0 +1,7 @@
+package main
+
+type AutoGenerated struct {
+	User struct {
+		Name string `json:"name"`
+	} `json:"user"`
+}