cleanup: use standard Golang errors package

"github.com/pkg/errors" does not offer more functionlity than that we
need from the standard "errors" package. With Golang v1.13 errors can be
wrapped with `fmt.Errorf("... %w", err)`. `errors.Is()` and
`errors.As()` are available as well.

See-also: https://tip.golang.org/doc/go1.13#error_wrapping
Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/util/util.go

@@ -18,6 +18,8 @@ package util
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"math"
 	"os"
 	"path"
@@ -25,7 +27,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
@@ -145,7 +146,7 @@ func ValidateDriverName(driverName string) error {
 			err = errors.New(msg)
 			continue
 		}
-		err = errors.Wrap(err, msg)
+		err = fmt.Errorf("%s: %w", msg, err)
 	}
 	return err
 }