config: replace uses of deprecated io/ioutil

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

config/config.go

@@ -8,7 +8,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"regexp"
 	"strconv"
 	"strings"
@@ -699,7 +699,7 @@ func LoadFile(path string) (*Config, error) {
 		return nil, cferr.Wrap(cferr.PolicyError, cferr.InvalidPolicy, errors.New("invalid path"))
 	}
 
-	body, err := ioutil.ReadFile(path)
+	body, err := os.ReadFile(path)
 	if err != nil {
 		return nil, cferr.Wrap(cferr.PolicyError, cferr.InvalidPolicy, errors.New("could not read configuration file"))
 	}