ioutil -> os (facebookincubator#45)

Summary:
ioutil package is deprecated

Pull Request resolved: facebookincubator#45

Reviewed By: mimir-d

Differential Revision: D45731080

Pulled By: pmazzini

fbshipit-source-id: 6f638d12f704667fb8a63fb64decf3d6bc5d7fad

go.sum

@@ -1,3 +1,4 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/fsnotify/fsnotify v1.6.0 h1:n+5WquG0fcWoWp6xPWfHdbskMCQaFnG6PfBrh1Ky4HY=
 github.com/fsnotify/fsnotify v1.6.0/go.mod h1:sl3t1tCWJFWoRz9R8WJCbQihKKwmorjAbSClcnxKAGw=
 github.com/golang/glog v1.1.0 h1:/d3pCKDPWNnvIWe0vVUpNP32qc8U3PDVxySP/y360qE=

lib/config.go

@@ -10,8 +10,8 @@ package dhcplb
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"net"
+	"os"
 	"path/filepath"
 	"strings"
 	"time"
@@ -69,15 +69,15 @@ type Overrides struct {
 // file, an integer version and a ConfigProvider and will return a pointer to
 // a Config object.
 func LoadConfig(path, overridesPath string, version int, provider ConfigProvider) (*Config, error) {
-	file, err := ioutil.ReadFile(path)
+	file, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
 
 	overridesFile := []byte{}
 	// path length of 0 means we aren't using overrides
 	if len(overridesPath) != 0 {
-		if overridesFile, err = ioutil.ReadFile(overridesPath); err != nil {
+		if overridesFile, err = os.ReadFile(overridesPath); err != nil {
 			return nil, err
 		}
 	}