format with gofumpt (#18184)

* gofumpt -w -l .

* gofumpt -w -l -extra .

* Add linter

* manual fix

* change make fmt

routers/api/v1/repo/release_attachment.go

@@ -178,7 +178,7 @@ func CreateReleaseAttachment(ctx *context.APIContext) {
 	}
 	defer file.Close()
 
-	var filename = header.Filename
+	filename := header.Filename
 	if query := ctx.FormString("name"); query != "" {
 		filename = query
 	}