Sort repository tree entries in natural way (#2506)

* Sort repository tree entries in natural way

* Fix sort for different length strings with first parts equal

* Improve test case

* Refactor return statements

* Update gitea/git dependency

modules/base/natural_sort_test.go

@@ -0,0 +1,24 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package base
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNaturalSortLess(t *testing.T) {
+	test := func(s1, s2 string, less bool) {
+		assert.Equal(t, less, NaturalSortLess(s1, s2))
+	}
+	test("v1.20.0", "v1.2.0", false)
+	test("v1.20.0", "v1.29.0", true)
+	test("v1.20.0", "v1.20.0", false)
+	test("abc", "bcd", "abc" < "bcd")
+	test("a-1-a", "a-1-b", true)
+	test("2", "12", true)
+	test("a", "ab", "a" < "ab")
+}