Update CI go version

.travis.yml

@@ -1,7 +1,10 @@
 language: go
 sudo: false
+os:
+  - osx
+  - linux
 go:
-  - 1.11.x
+  - 1.12.x
 env:
   - GO111MODULE=on
 install: true

README.md

@@ -6,7 +6,7 @@
 [![license](https://img.shields.io/github/license/arturalbov/atomicf.svg)](https://github.com/arturalbov/atomicf/blob/master/LICENSE)
 [![contributors](https://img.shields.io/github/contributors/arturalbov/atomicf.svg)](https://github.com/arturalbov/atomicf/graphs/contributors)
 [![contribute](https://img.shields.io/badge/contributions-welcome-orange.svg)](https://github.com/arturalbov/atomicf/graphs/contributors)
-[![telegram](https://img.shields.io/badge/Telegram-%40arturalbov-blue.svg?style=social&logo=telegram)](https://t.me/username)
+[![telegram](https://img.shields.io/badge/Telegram-%40arturalbov-blue.svg?style=social&logo=telegram)](https://t.me/arturalbov)
 
 ```$xslt
 import "github.com/arturalbov/atomicf"

file_test.go

@@ -20,7 +20,7 @@ func TestAtomicFile_CreateWrite(t *testing.T) {
 	defer os.RemoveAll(dir)
 
 	fileName := filepath.Join(dir, "atomic-test")
-	atomic, err := OpenFile(fileName, os.O_CREATE|os.O_SYNC|os.O_APPEND|os.O_WRONLY, 0666)
+	atomic, err := OpenFile(fileName, os.O_CREATE|os.O_SYNC|os.O_WRONLY, 0666)
 
 	if err != nil {
 		t.Errorf("error open atomic file %s: %v", fileName, err)
@@ -64,7 +64,7 @@ func TestAtomicFile_WriteAt(t *testing.T) {
 		t.Fatalf("error creating test atomic file: %v", err)
 	}
 
-	atomic, err := OpenFile(fileName, os.O_CREATE|os.O_SYNC|os.O_APPEND|os.O_WRONLY, 0666)
+	atomic, err := OpenFile(fileName, os.O_CREATE|os.O_SYNC|os.O_WRONLY, 0666)
 	if err != nil {
 		t.Errorf("error open atomic file %s: %v", fileName, err)
 		return
@@ -120,7 +120,7 @@ func TestAtomicFile_Recover(t *testing.T) {
 		t.Fatalf("error creating test atomic file: %v", err)
 	}
 
-	atomic, err := OpenFile(filepath.Join(dir, atomicFileName), os.O_CREATE|os.O_SYNC|os.O_APPEND|os.O_WRONLY, 0666)
+	atomic, err := OpenFile(filepath.Join(dir, atomicFileName), os.O_CREATE|os.O_SYNC|os.O_WRONLY, 0666)
 	if err != nil {
 		t.Errorf("error open atomic file %s: %v", logFileName, err)
 		return