docs(goctl): goctl 1.3.4 migration note (#1780)

* docs(goctl): goctl 1.3.4 migration note

* adds a simple lang check
* adds migration notes

* chore: remove i18n

* chore: remove todo

tools/goctl/model/sql/command/migrationnotes/v1.3.4.go

@@ -0,0 +1,57 @@
+package migrationnotes
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	"github.com/urfave/cli"
+)
+
+func migrateBefore1_3_4(ctx *cli.Context) error {
+	dir := ctx.String("dir")
+	style := ctx.String("style")
+	ok, err := needShow1_3_4(dir, style)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return nil
+	}
+
+	fmt.Println(`It seems like that your goctl has just been upgraded to version 1.3.4 or later, which refactored the code of the model module. The original XXXmodel.go has been split into XXXmodel_gen.go (read-only) and XXXmodel.go. You just need to follow these steps to complete the migration:
+1. back up the original XXXmodel.go (make sure the file name is no longer in the current directory)
+2. re-run the generate command (a new XXXmodel.go will be created)
+3. populate XXXmodel.go with the code that is not generated by goctl according to the comments in XXXmodel_gen.go`)
+
+	return nil
+}
+
+func needShow1_3_4(dir, style string) (bool, error) {
+	files, err := ioutil.ReadDir(dir)
+	if err != nil {
+		return false, nil
+	}
+	// Returns false when the directory contains a file with the suffix "_gen.go"
+	// In addition, it returns true if it contains a model file extension.
+	// In other case, false is returned.
+	for _, f := range files {
+		if f.IsDir() {
+			continue
+		}
+		if strings.HasSuffix(f.Name(), "_gen.go") {
+			return false, nil
+		}
+	}
+	modelSuffix, err := getModelSuffix(style)
+	if err != nil {
+		return false, err
+	}
+	for _, f := range files {
+		if !f.IsDir() && strings.HasSuffix(f.Name(), modelSuffix) {
+			return true, nil
+		}
+	}
+	return false, nil
+
+}