ini: change minimum Go requirement to 1.6

.travis.yml

@@ -1,7 +1,6 @@
 sudo: false
 language: go
 go:
-  - 1.5.x
   - 1.6.x
   - 1.7.x
   - 1.8.x

ini.go

@@ -1,3 +1,5 @@
+// +build go1.6
+
 // Copyright 2014 Unknwon
 //
 // Licensed under the Apache License, Version 2.0 (the "License"): you may

parser.go

@@ -390,8 +390,7 @@ func (f *File) parse(reader io.Reader) (err error) {
 		// Section
 		if line[0] == '[' {
 			// Read to the next ']' (TODO: support quoted strings)
-			// TODO(unknwon): use LastIndexByte when stop supporting Go1.4
-			closeIdx := bytes.LastIndex(line, []byte("]"))
+			closeIdx := bytes.LastIndexByte(line, ']')
 			if closeIdx == -1 {
 				return fmt.Errorf("unclosed section: %s", line)
 			}