Generate Bindata iff TAGS="bindata" and not up-to-date (#10004)

* Only generate bindata if necessary

* Only generate bindata if they are not up-to-date

* generate a hash of the fileinfo and use that to keep up-to-date

* Newer test is redundant

* handle missing bindata and clean

* Only update hash after successful write

* switch to sha1 hash

* Apply suggestions from code review

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

modules/templates/main.go

@@ -1,23 +0,0 @@
-// +build ignore
-
-package main
-
-import (
-	"log"
-	"net/http"
-
-	"github.com/shurcooL/vfsgen"
-)
-
-func main() {
-	var fsTemplates http.FileSystem = http.Dir("../../templates")
-	err := vfsgen.Generate(fsTemplates, vfsgen.Options{
-		PackageName:  "templates",
-		BuildTags:    "bindata",
-		VariableName: "Assets",
-		Filename:     "bindata.go",
-	})
-	if err != nil {
-		log.Fatal("%v", err)
-	}
-}

modules/templates/templates_bindata.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
 
+//+build bindata
+
 package templates
 
-//go:generate go run -mod=vendor main.go
+//go:generate go run -mod=vendor ../../scripts/generate-bindata.go ../../templates templates bindata.go